Symposium Introduction

A regular thought about Evidentialism, the view that one may believe only on the basis of one’s evidence, is that it is intrinsically opposed to religious commitment. This is partly because religious belief is regularly taken to be posited on simple faith, belief without and perhaps contrary to one’s evidence. But this commitment about evidential backing for religious belief is itself controversial, as support for religious belief can be garnered from many sources—reflection, natural theology, revelation, and tradition only to begin. Consequently, the demands of evidence and what constitutes evidence is not a debate exclusively between the religious believers and skeptics, but it is a debate that may be productively run internal to the religious perspective.

Anthony Booth’s Islamic Philosophy and the Ethics of Belief is exemplary of this debate, and in particular his case is that it is run internal to the medieval Islamic tradition. Given that many of the categories of this debate are ones that arose after the publication of William Kingdon Clifford’s epochal “The Ethics of Belief,” a good deal of the discussion requires taking on a lens of twentieth- and twenty-first-century debates about the ethics of belief and viewing past debates through it. Once these categories are in place, new options and lines of reasoning emerge that seem unique to the Islamic tradition. As Booth frames it, the intersecting medieval Islamic philosophical programs, that of falasifa, yield a wide breadth of debate:

I consider the falasifa’s intellectual project as one primarily engaged in the ethics of belief. That is, they were concerned with understanding the epistemic (and in many cases the non-epistemic) conditions of justified belief; in particular, they sought to understand when belief is blameworthy, and, as in the case of apostasy, when it is punishable by death. (3)

In this regard, evidentialism is not only a cognitive norm, but it is, internal to the religious traditions, a theological norm, too.

Of particular interest for Booth is belief based on prophecy, since whether prophecy counts as evidence in many ways depends on whether there really are gods (or a God), prophets, and the kind of communication at issue. As Booth captures the problem:

If we take an Evidentialist view, then we must, on pain of special pleading, consider a theistic belief justified just in case it is believed on the basis of sufficient evidence. In other words, a religious belief’s correctness is determined by its truth conditions. (9)

This does create quite the epistemic challenge—that prophecy can be evidence only if it really is prophetic, which in many ways is exactly the question. The falasifa Booth identifies as unique and of particular interest on this matter are those he identifies as Moderate Evidentialists. Al-Farabi, in particular, took on a demanding program with regard to knowledge (one Booth sees as having a witheringly demanding requirement of knowing that one knows as a condition for first-order knowledge), and so had a form of infallibilist evidentialism constrain correct management for beliefs by the Prophet. But we, on the other hand, cannot live up to those demands. Instead, Booth’s version of al Farabi (and Averroes later) holds, “it is possible for us, ordinary humans, to reason our way to justified belief in religious and moral matters, but it will necessarily stop short of proper certainty” (21).

In stark contrast, Booth brings Al-Ghazali’s The Incoherence of the Philosophers to bear on the matter, and he shows a contrary trend of what he calls “Moderate Anti-Evidentialism.” Al-Ghazali and the Ash’arite thinkers reacted to the rationalism of the Averroist evidentialists, and held that, as Booth frames it, “for all propositions p, except for one very special proposition, p should be believed because God wills it” (30). God’s will plays a unique role in the normativity of not only action (as we might see with commandments, for example) but of belief, too. The one exception, we should note, is the belief that the prophet is a genuine prophet. Identifying the legitimate prophet, as it turns out, is the only freestanding epistemic task for any believer. And so, it seems, both the Moderate Evidentialist and the Moderate Anti-Evidentialists in this tradition share the same problem.

The key to all of these debates, by Booth’s lights, is identifying “the epistemic elite,” those for whom more reflection and evidence is possible, and so those for whom the intellectual demands are greater. For the Moderate Evidentialists, al-Farabi and Avicenna, prophets must be philosophers, capable of having reflective knowledge of when they know. (Again, they must live up to the KK-requirement for knowledge.) In particular, these epistemic elite must be capable of identifying their beliefs as certain. Booth presents the requirements as follows:

S is absolutely certain that P if:

  1. S believes that P.
  2. S believes that P for epistemic reason.
  3. S (infallibly) believes 2.
  4. S (infallibly) believes that it is impossible for there to be no epistemic reasons for her to believe that P.
  5. S (infallibly) believes that there can be no time at which there is no epistemic reason for her to believe that P.
  6. Conditions 1–5 hold essentially, not accidentally (pp. 45–50).

In short, for the Moderate Evidentialist such as al-Farabi, certainty is no accident, but is a cognitive success that is achieved not only reflectively, but infallibly, and in a way that reflects the necessity of the truths grasped.

The anti-Evidentialist al-Ghazali, however, holds that such knowledge is beside the point about whether one ought to believe, since irrefutable evidence holds no normative weight for those who hold that it is God’s will that is the source of cognitive normativity. Again, the exception is that of identifying the genuine prophet, which Booth holds al-Ghazali takes to be a matter of “testing whether following the prophet’s practical guidance really does lead us to live happier lives—whether it leads to a state where our hearts have been ‘purified’” (61). But this puts the anti-Evidentialst in an epistemic pickle, since now there is a gap between identifying the truths about what makes humans flourish and happy (presumably things we, if al-Ghazali is right, would need a prophet for) and whether the prophet at issue correctly says those things. We may take the former on authority, but that precisely is where the issue lies—properly identifying the authority. In the end, the problem comes to who is the better “persuader,” which is a solution at which any worried about apostacy should blanch.

A consequence of this debate is that the sides come out with a sense of intellectual humility with regard to identifying true prophets and the correct content of prophecy. This moderacy, Booth holds, has significant political implications. In particular, a form of liberalism arises as a state-side manifestation of the fallibilism that is necessary. Al-Farabi holds that only the prophet herself could have perfect knowledge, and further, there are times when the prophet is absent and cannot speak to issues of the day. Just as there are perfect and imperfect knowers, there are perfect and imperfect cities, and we are in a sense in a position of inhabiting both of the latter. Of the imperfect cities Al-Farabi holds that the democratic city is best and capable of pockets of perfection. For those not living in a time of prophecy, “we must concern ourselves with something less than absolute certainty” (81), and so we must resolve to respect the views and lives of others pursuing God and the good in their respective ways. In turn, Booth holds that this line of thought yields goods in Islamic critique of Islamist extremism, and it provides a model for religious belief in pluralist societies.

Islamic Philosophy and the Ethics of Belief is controversial both in its religious epistemic program and in its political application. It is a great pleasure to bring together these scholars to discuss Booth’s challenging and important book.

Sabeen Ahmed


Islamic Philosophy and the Ethics of Belief by Anthony Robert Booth

Anthony Robert Booth, in Islamic Philosophy and the Ethics of Belief, advances a novel categorization of rationalist, medieval epistemology as what he calls “Moderate Evidentialism,” with the “Moderate anti-Evidentialism” of the orthodox Ash’arite theologians as the counterpoint to the writings of the Peripatetic falasifa. Booth’s analysis is oriented toward two significant aims: first, it proffers to unify the underlying philosophical commitments of the three major falasifa—Abu Nasr al-Farabi, Ibn Sina (Avicenna), and Ibn Rushd (Averroes)—against those of Abu Hamid al-Ghazali, the Ash’arite credited with delegitimizing the rationalist project; and second, it uses these philosophical distinctions to shed light on contemporary philosophico-theological debates on Islamic politics. These aims are certainly ambitious, but Booth’s background in analytic epistemology, ethics, and philosophy of mind lend a unique clarity and systematicity to their notoriously complex subject matter.

I center my concern with Booth’s book around his discussion of al-Farabi, as al-Farabi occupies the focal point of his theory of Moderate Evidentialism. Specifically, I take up Booth’s lack of clarity as to the nature of the Prophet and of God, and the consequent implications it has on his assessment of al-Farabi’s notion of certitude. I myself do not offer any definitive interpretation of al-Farabi’s theory of prophecy; it is well known that he never makes explicit the precise nature of prophethood, whether because much of his work is lost to us or because we are unsure how genuine al-Farabi’s belief in prophecy actually was. Herbert Davidson, one of the leading authorities on the medieval reception of Aristotle’s theory of intellect, notes the possibility that many of al-Farabi’s views “were only intended to veil his real views from conservative religious leaders” (Davidson 1972, 143–44). What is consistent among medievalists, however, is that medieval epistemology cannot be considered separately from medieval cosmology, particularly since al-Farabi, Avicenna, and Averroes alike wrote within the framework of Plotinian emanation. This is a point that Booth alludes to briefly at various points in his work, but is never taken up as the metaphysical background of his own analysis of Farabian certitude.

From the outset, Booth contours his exploration of the falasifa as “explicitly advocating an Islamic philosophy” which worked to “[further] the theistic enterprise” (Booth 2016, 8). He further qualifies their philosophical project as aiming to authenticate Hadith or, “in other words, the process of discerning prophetic speech” (Booth 2016, 10). This characterization of medieval, Peripatetic philosophy is quite bold, considering that neither al-Farabi nor Averroes explicitly mention, in their philosophic writings, Islam, the prophet Muhammad, or the Qur’an by name. In the case of al-Farabi, the generalized figure of the prophet is mentioned only in his al-Madina al-Fadila (The Virtuous City), and is notably absent in the Conditions of Certitude, the “Book of Rhetoric,” and in his seminal political work, The Attainment of Happiness. Even Averroes, who does mention the Prophet in his commentary on Plato’s Republic, expresses that prophethood, as a condition for rulership, would be preferable rather than necessary (it should be noted that Averroes also mentions the Qur’anic verse 3:7 in his Decisive Treatise, although he does so to promote the compatibility of philosophical inquiry with the tenets of revelation as commonly understood; see Ahmed 2016).

That neither al-Farabi nor Averroes advocate for an explicitly Islamic philosophy is crucial, as it reinforces the profound significance of understanding their work against their Aristotelian Neoplatonic theory of emanative cosmology. Al-Farabi was particularly important in this regard; it was he who bridged the gap between the celestial spheres and the sublunar world by identifying the Active Intellect as the tenth Intelligence, a characterization absent in the writings of Plotinus, Themistius, and Alexander of Aphrodisias. His further identification of the Active Intellect as the external “source” of the intelligibles is precisely what allows for the attainment of human intellectual perfection. In the Conditions of Certitude, al-Farabi explicitly states that the meaning of truth is “the relation of what belongs to the belief to the object of belief insofar as the latter is external to the soul” (al-Farabi, Ketāb šarāʾe al-yaqīn, 97, my emphasis).

Al-Farabi’s Conditions of Certitude serves as the focus of Booth’s development of the falasifa’s Moderate Evidentialism, and it is here where the consistency of the theory is most opaque. Booth, drawing from Deborah Black, correctly identifies al-Farabi’s theory of certainty as containing strict K-K requirements, or the requirement that “in order to have certainty that p, it must be necessary that one could not but have been certain that p” (Booth 2016, 20). Al-Farabi himself classifies six qualifications for absolute certitude, and Booth highlights the fourth and fifth as indicative of the need for prophecy. In Black’s interpretation of the Conditions of Certitude, al-Farabi states that “it is impossible that p not be true” (or, as Booth states, the “necessity condition”) and that “there is no time at which p can be false” (or the “eternity condition”) (see Booth 2016, 44). Booth, after offering a more nuanced rewrite of these conditions, understands them to be illustrating “different kinds of epistemic possibility” rather than as distinguishing between epistemic and metaphysical conditions (Booth 2016, 48). This characterization is relatively uncontroversial, particularly since al-Farabi’s theory of emanation identifies four types of intellect that a human can possess: potential intellect, actual intellect, agent (or active) intellect, and acquired intellect. More peculiar is Booth’s assertion that only the prophet is capable of attaining the highest level of epistemic certainty: only she can fulfill al-Farabi’s sixth condition that the epistemic acquisition of the first five characteristics of certitude “does not happen accidentally, but essentially” (al-Farabi, Ketāb šarāʾe al-yaqīn, 97). Booth further qualifies this position by invoking the “prophetic psychological makeup” unique to the prophet, allowing her to “have absolute certainty towards those propositions about which there can be absolute certainty—necessary, eternal truths” (Booth 2016, 49). Indeed, this qualification is what justifies Booth’s Moderate Evidentialism: although only prophets can have certitude absolutely, non-prophets can have justified beliefs without the need for absolute certainty. The role of the prophet is precisely why the falasifa advocated for a type of Evidentialism whatever.

That Booth discusses Farabian certainty without appealing to his emanative cosmology is troubling. We must remember that al-Farabi’s cosmology—taken up by Avicenna and Averroes in his wake—is directly tied to the Active Intellect, which Booth does address in brief. The existence of the Active Intellect, with its external permanency, necessity, and eternality, is the basis for al-Farabi’s characterization of the four types of human intellect: “It becomes the task of the active intellect,” Davidson writes, “to complete the perfection of the sublunar world by leading the human intellect from potentiality to actuality” (Davidson 1972, 137). It is the attainment of the acquired intellect which fulfills the K-K condition needed for absolute certainty and, as such, intellectual perfection. Fazlur Rahman summarizes the acquisition of this intellect in the following manner:

Every intelligible thing can be contemplated by the actual intellect by receiving its form and since the actual intellect is itself now an intelligible thing, it can therefore know itself. When thus our intellect becomes both self-intelligible and self-intellective, becomes a form of form, it becomes, in al-Farabi’s terminology, “acquired intellect.” (Rahman 1958, 12)

Why is this emphasis on acquired intellect significant, and why is it troubling that Booth fails to mention it in his analysis of certitude? Because for al-Farabi, the acquired intellect is the only part of the human soul that is immortal. And because the acquired intellect is the agent’s knowledge that she knows the necessary, eternal intelligibles (and hence, K-K in nature), it is indistinguishable from the acquired intellect of any other agent. The first consequence is, of course, that there is no possibility for individual immortality: immortality is predicated instead on the attainment of intellectual perfection. The second consequence is that Booth’s emphasis on the falasifa’s promotion of a distinctly Islamic philosophy loses strength. Indeed, much of why the dialectical theologians, the Mutakallimun, charged the Peripatetic Islamic philosophers for apostasy was for their denial of individual immortality, which is one of the reigning characteristics of Islam itself.

Bracketing the theological implications of this cosmology, we might turn to the inconsistency it produces for Booth’s characterization of the prophet as the only agent who can satisfy all six of al-Farabi’s requirements for absolute certitude. Booth identifies a “certain prophetic ability” as the necessary bridge to essential understanding, insofar as “God has predetermined that she [the prophet] will know all intelligibles by giving her a special faculty of imagination” (Booth 2016, 56). It is unclear whether Booth is here enumerating two faculties of imagination—one “ordinary” and one “special”—which allows for the existence of this “certain prophetic ability,” but it is in any case a mischaracterization to denote this capacity as predetermined by “God.” God, for the falasifa, is analogized most closely with the Active Intellect; explicit textual evidence thereof is almost impossible to identify, however, as the medieval philosophers—and especially al-Farabi and Averroes—offered theoretically inconsistent accounts of intellection across a number of their respective works. However, it is indisputable that the complexity of their own views of the Divine is intimately interwoven with their understandings of epistemology, cosmology, ethics, and political philosophy.

In any case, Booth is right to highlight the imaginative faculty as that which is unique to al-Farabi’s brief characterization of the prophet. Since the imaginative faculty is separate from the cognitive and intellective faculties, however, it is unlikely that al-Farabi, dedicated as he was to Aristotelian epistemology, would have believed that a “perfect” faculty of imagination could supply the agent with intellectual perfection. More simply, one can have a powerful imagination whether or not they possess the acquired intellect. Miriam Galston suggests as much when she states that there is a “crucial distinction between a powerful imagination independent of rational control and a powerful imagination under the direction of reason” (Galston 1990, 45). As such, we might say that there exist three types of “elite”: the philosopher, the prophet, and the philosopher-prophet. Booth is undoubtedly concerned with the third of these—that agent who has both the acquired intellect indicative of intellectual perfection and the superior imaginative faculty that allows her to convey the intelligibles in a manner suitable for all types of citizens. This “higher level of prophet,” as Davidson writes, “is found exclusively among men who have passed through all the stages of human intellectual development, reached the level of ‘acquired intellect,’ and had the active intellect ‘enter’ them” by means of the imaginative faculty (Davidson 1972, 147). The subtle yet significant implication here is that an agent can have the acquired intellect—and thereby possess absolute certitude—without being a prophet.

It seems uncontroversial to claim that the philosopher proper—she who has perfected her intellect—can have a level of absolute certainty of eternal truths without also being a prophet: it is the philosopher and not the prophet or philosopher-prophet, after all, that al-Farabi identifies as the virtuous ruler in The Attainment of Happiness. To deny this possibility would be to elevate al-Farabi’s ambiguous writings on prophecy to the status of a definitive, philosophical commitment, no less than to undermine the cosmological commitments of the falasifa altogether. Though his arguments for the intellectual primacy of the prophet are deeply compelling, Booth’s negligence of medieval, Peripatetic cosmology diminishes the force of the theory he intends to advance.


Ahmed, Sabeen. “The Genesis of Secular Politics in Medieval Philosophy: The King of Averroes and the Emperor of Dante.” In “Praxis, Virtues, and Values: The Legacies of Aristotle,” special issue of Labyrinth: An International Journal for Philosophy, Value Theory, and Sociocultural Hermeneutics 18.2 (2016) 209–31.

Al-Farabi, Abu Nasr. Ketāb šarāʾe al-yaqīn. Ed. in ʿAjam and Faḵrī, IV: pp. 97–104.

Booth, Anthony Robert. Islamic Philosophy and the Ethics of Belief. London: Palgrave Macmillan, 2016.

Davidson, Herbert A. “Alfarabi and Avicenna on the Active Intellect.” Viator 3 (1972) 109–78.

Galston, Miriam. Politics and Excellence: The Political Philosophy of al-Farabi. Princeton: Princeton University Press, 1990.

  • Anthony Booth


    Reply to Ahmed

    I am extremely grateful to Sabeen Ahmed for writing this very insightful reply to my work, and summarising what I was trying to do in it so nicely. The nub of her complaint seems to be that in my interpretation of al-Farabi, I did not pay enough heed to the indisputable connection between al-Farabi’s cosmology, and epistemology, ethics, and political philosophy. At stake here is the important issue as to how committed to a kind of proto-secularism al-Farabi and the rest of the Falasifa in fact were—failure to do justice to the cosmology underlying their thought has made me fail to appreciate the potential secular impulses in their thought.

    Ahmed mentions, rightly, that “medieval epistemology cannot be considered separately from medieval cosmology, particularly since al-Farabi, Avicenna, and Averroes alike wrote within the framework of Plotinian emanation.” And that it is something that I “allude[s] to briefly at various points.” Let me now take the opportunity to make it completely clear that I think that in my interpretation of al-Farabi, his emanationist cosmology is at the centre of everything. I very much appreciate the opportunity to make this clear here since my meaning seems to have been less than fully clear in the book.

    I think the connection between al-Farabi’s cosmology and epistemology is something like the following. I think the 6th condition on certainty—as developed in al-Farabi’s The Conditions of Certainty—denotes an extremely stringent K-K condition (more so than other K-K conditions) where one has to understand why it is that one can apprehend intelligibles (to use the Aristotelian term) at all. So to satisfy this condition, I think, it is not enough merely to become an acquired intellect—a state where one has achieved union with the active intellect, such that knowledge of the intelligible is ultimately self-knowledge (as the passage that Ahmed quoted from Rahman illustrates). Put differently, that we have become an acquired intellect is compatible with our not understanding why we have so become. It is the capacity for carrying out that last bit of cognitive labour that marks out the prophet’s perfected state of certainty. And she is able to do so only if an emanationist cosmology obtains: because the active intellect is an emanation from the First Intellect or Plotinus’s One, all the intelligibles are in some deep ontological way bound up. The higher up the level of emanation an intelligible resides, the more unity with the other intelligibles it displays, until we go so far up the sequence that all the intelligibles can no longer be identified as discrete. The power of the prophet’s imagination then allows the prophet to grasp the intelligibles together, in their unity, and this allows her to understand how and why she, qua intelligible, is able to do so—thus her state of certainty is incompatible with evidential luck (luck that she has evidence for p) as well as veritic luck (luck that the proposition believed is true, given her evidence). Unlike for Avicenna, I think that for al-Farabi it is the mode in which the prophet grasps essences that marks them out as a prophet—prophets do not therefore have esoteric knowledge, in the sense that they have epistemic access to intelligibles that other humans do not. Further, in the prophet’s state of certainty the intellectual and the other capacities then lie united, mirroring how the further up in the emanated spheres one travels, the more unity between things one finds. This is important politically, I think, because in ordinary humans the intellectual and other virtues lie in pieces, and humans find their felicity when the virtues are put together again. But since no one human can do this alone—prophets aside—we must find ways to work together in harmony in order for us to find true felicity.

    Following a suggestion from Miriam Galson, Ahmed suggests that for al-Farabi “we might say that there exist three types of ‘elite’: the philosopher, the prophet and the philosopher-prophet” and that a philosopher “can have the acquired intellect—and thereby possess absolute certitude—without being a prophet.” And since al-Farabi explicitly identifies the philosopher as the ruler of the virtuous city, this may give us reason to think of Farabian political philosophy as secular. I think that reading is hard to square with how centrally the generalized idea of the prophet as political leader figures in his central text The Perfect State, and I have doubts as to whether even in The Attainment of Happiness he is does not in fact have in mind the philosopher-prophet (and not the philosopher) as Ahmed conceives the notion. My disagreement with Ahmed is that I think that while I think that al-Farabi concedes that non-prophets can attain the acquired intellect, I do not think it follows (for al-Farabi) that non-prophets can, as she puts is, “thereby possess absolute certitude.” I think that al-Farabi thinks that they cannot. And I think for him it is only the person who possesses this certainty who—because they cannot be prone to akrasia—will have the right moral character, and—because their state of certainty comes with practical and rhetorical perfection—will have the requisite political abilities to lead.

    But having said all that, as I wrote in my reply to Ethan Mills, I suspect there may be a way of reading all this in a secular way, where the figure of the prophet is really a regulative ideal in which we are able to see the principled connection between intellectual expertise and rhetorical ability. I also suspect that one can read the idea that God predetermines the world such as to ensure that someone has the requisite prophetic abilities in a secular register. And so that “God” is really to be thought of as something more akin to the First Intellect in an emanationist cosmology. As al-Farabi himself puts it: “Because the active intellect is an emanation from the existence of the first cause, it is possible due to this to say that the first cause is what brings revelation to this human being by the intermediary of the active intellect” (al-Farabi, Political Regime, sec. 80).



    Al-Farabi. The Political Regime (Al-Siyāsah al-Madanīyyah). Translated by Charles Butterworth, 2001, in Butterworth (ed.), Alfarabi: The Political Writings, vol. 2.

John Casey


Review of Anthony Robert Booth’s Islamic Philosophy and the Ethics of Belief

My comment on Anthony Robert Booth’s Islamic Philosophy and the Ethics of Belief will focus narrowly on the framing of the problem of prophecy early in chapter 1. My question is a very simple one: What is the problem of prophecy? I ask this because, as a general notion, prophecy might be understood to mean distinct things and raise a number of different epistemological questions.

The term “prophecy” first appears early in chapter 1, in the course of a discussion of the general problem of evidentialism. Prophecy is not explicitly defined, but it’s clearly identified with sacred texts:

What is prophecy’s unique epistemic role? Does Evidentialism entail that we can reason our way, by investigating the world, into correct religious belief (if there is such a thing)? If it does, then it appears as if we can arrive at correct religious belief without consulting divine scriptures at all (9).

It is easy to see why prophecy so described is of central interest to the ethics of belief. In the first place, as Aikin pointed out in the introduction, contrary to a popular stereotype, philosophers of religion have long been concerned with the evidentiary value of prophetic utterances of various kinds. This is especially true when these prophetic utterances dictate the core message and core beliefs of the religion and, crucially, when failure to affirm these beliefs is punishable by death (on earth) or hell (after death). Second, these philosophers have not only been just interested in these questions, some of them taken decidedly evidentialist positions on them. Third, Islam, like Christianity, is a religion of the book. Its central claims are found in the pages of a special kind of religious text. In the case of Islam, the special text, the Koran, was dictated to the Prophet Muhammad. Christianity’s special text, the Gospels, were written by humans divinely inspired, at least on one telling. Knowledge of the claims made in these texts is of ultimate practical and theoretical value.

The nature of this prophetic evidence, Booth argues, poses a conundrum which sharply distinguishes evidentialists from anti-evidentialists. On the one hand, evidentialism suggests that it is possible we can reason our way to religious belief without the need for scriptures at all. Should it be the case, however, that we require the sacred texts for some reason, evidentialists will still insist that we will need a method for sorting out which sacred text to believe and which not to believe. Sacred texts do not free us from the obligations of evidence. Such dependence on evidence, however, calls into question the uniqueness of revelation, which, in this circumstance, would rely for its rational acceptability on evidence different from revelation. Alternatively, should we consider the problem through the lens of the anti-evidentialist, whereby scripture is to be believed for non-epistemic reasons, then we have to face the evidential question as to how to sort out real scripture from fake scripture. This dilemma, according to Booth, “stands as the central problem of medieval Islamic philosophy” (10).

It is clear why prophecy is central the argument in the book. But the central problem just described, I think, varies significantly depending on what one means by prophecy. To illustrate this point, I would like to borrow some distinctions from Aquinas’s discussion of faith and evidence in the early chapters of the Summa Contra Gentiles. Early in chapter 3, Aquinas distinguishes between two different types of truths about God. One kind of truth about God is one someone might discover on their own, by the natural light of reason (though with great difficulty and risk of error, as Aquinas urges). Aquinas’s examples of this sort of claim are that God exists and that God is one. The other type of revealed truth “exceed the ability of human reason,” such as the fact, for Christianity, that God is triune. There’s no way you’re going to get to the idea that God is triune under your own steam. Such a claim has simply to be revealed to you.

Aquinas will go on to argue that revelation is nonetheless necessary for both kinds of divine truths. It is necessary in the first place because knowledge of these things is essential for salvation and the vast majority of humans do not have the skill, the time, or the patience to sort through the various arguments for the existence of God. Besides, even when they do find the time and have the expertise, the risk that they misplace something in the middle of a very long chain of reasoning is very high, and thus must live with nagging uncertainty that they’ve made a mistake. It’s better, in other words, that such truths be delivered to us via revelation. For Aquinas this revelation is obviously centered on the account in the Gospels. The case for the truths of the second kind is an easier one: we’ll never come to them on our own, so we simply need to be told.

The nature of this revelation, and our relationship to its revelation, however, points to yet a third kind of prophetic claim. Christianity and Islam are historical religions, the central claims of which include knowledge of specific historical events and individuals. No amount of natural reason is going to lead you to the truth of the claim, for instance, that Muhammad or Jesus existed. These historical truths are unlike the Trinity-type claims because they’re completely clear to witnesses to the events. Some of the claims in scripture, in other words, are completely ordinary claims which, presumably, would not have posed unique questions of credibility for those who witnessed them. For later readers of scripture, however, their credibility is on par with the credibility we assign to historical texts. For Aquinas, claims of the second type provide the evidence for claims of the former kind. The ordinariness of the historical claims, that such-and-such people existed and did-such-and such things. Aquinas, of course, is an evidentialist about these matters.

In light of this, I’d like to close with some questions: Does the problem of prophecy exist in the same way for the living witness to prophets’ utterances and deeds as it does for later readers of accounts of them? Or does the problem only regard the credibility of the original prophet? Finally, does the problem of prophecy vary with regard to whether the question is solvable by the natural light of reason or completely beyond human understanding?

  • Anthony Booth


    Reply to Casey

    John Casey raises some very interesting questions for me. Let me now try to do something by way of answering them. I agree with Casey that the issue at stake concerns what prophecy is. In my book, I aimed to give an interpretation of the different accounts of prophecy within Islamic philosophy as different responses to what I called, as Casey notes, “the central problem of medieval Islamic philosophy”—viz. the issue regarding how Evidentialists can account for the epistemic uniqueness of prophecy. This is an issue, I argued, that is structurally very similar to the problem of expertise in modern epistemology of testimony. However, as I mentioned in the book, Evidentialism had a big draw from within Muʿtazilite Islamic theology since it makes it easy to account for a thesis that for the Muʿtazilites was of paramount importance: that God is just.

    In my book I tried to interpret some of the big figures of Islamic philosophy—al-Farabi, Ibn Sina, and Ibn Rushd—as advocates of a unified position, which I called “Islamic Moderate Evidentialism,” in contrast to what I called “Western Moderate Evidentialism,” and with the arch anti-philosopher al-Ghazali’s Anti-Evidentialism as the counterpoint. I take the position that Casey describes as belonging to Aquinas to be a species of Western Moderate Evidentialism. I define that view as follows:

    Western Moderate Evidentialism: For some propositions, non-epistemic reasons

    justify S’s believing that p.

    What are the propositions that the Western Moderate Evidentialist claims can be believed for non-epistemic reasons? In my interpretation of Aquinas, they are, those propositions for which a subject’s evidence is inconclusive, or simply could not settle the issue either way. For instance, to use an example from Casey, our evidence is neutral as regards the proposition that God is Triune—(according to Aquinas) our current evidence does not rule it out, but neither does it establish it. In such a case we can, indeed ought to, believe that God is Triune, but on the basis of non-epistemic reasons, on the basis if faith (when “faith” is interpreted as something non-epistemic). On this reading, belief on the basis of faith can never contradict reason, but faith nevertheless outruns the scope of reason. If we think that at least some of what is in revelation (prophecy) is of a kind that our evidence cannot establish (nor contradict) it, then the question of the unique epistemic role of prophecy is settled rather easily: it tells us what to believe on the basis of faith. Having established this, we may be able to give prophecy further epistemic roles—as Casey adduced—but they are rather thin without this underlying account of the relationship between faith and reason. However, there are some philosophical problems with Western Moderate Evidentialism. For instance, from an Evidentialist perspective, we might think that when our evidence is inconclusive as regards a proposition we ought to suspend judgment on it and not believe it for non-epistemic reasons, even where we have them.

    In contrast, Islamic Moderate Evidentialists hold the following:

    Islamic Moderate Evidentialism: For some subjects, non-epistemic reasons justify

    S’s believing that p.

    I think that the way that the Falasifa moderated their Evidentialism was not by restricting the number of propositions Evidentialism applies to, but by restricting who Evidentialism applies to. And for them it applies only to an epistemic elite. The question of who is this epistemic elite then naturally opens up, with each Falaysuf giving importantly different answers. I tried to argue, perhaps controversially, that for al-Farabi, only the Prophet constitutes a member of this elite class, since only she can attain absolute certainty. I argued this has all sorts of important political implications. And perhaps does so all the more because of how al-Farabi understood absolute certainty as satisfying very stringent K-K conditions that require both theoretical and practical perfection. As such we get, for al-Farabi, in the epistemic state of the prophet, a principled connection between expertise on a subject matter and the ability to communicate that expertise.

    This makes Casey’s final questions especially apposite:

    Does the problem of prophecy exist in the same way for the living witness to the prophet’s utterances and deeds as it does for later readers of accounts of them?

    Or does the problem only regard the credibility of the original prophet?

    I think the questions pertinent here because while the perfected epistemic state of the prophet will eo ipso come with perfected dialectical and rhetorical ability, surely the latter must be at least to a certain extent bound by space and time. That is, we may be able to imagine—pace al-Farabi—how the living witnesses to the prophet’s activities may have found them intellectually as irresistible it is possible for them to be. But how could the prophet’s rhetorical and dialectical ability be so good as to be so persuasive to people she has not yet met, and presumably (when we’re talking about infinite posterity) with an infinite number of possible background beliefs? So I think that al-Farabi is mostly interested about the credibility of the original prophet. But that once we see how that credibility is possible—via the principled connection of theoretical and practical virtue in the prophet’s state of absolute certainty, a state we cannot attain—some important political things follow. Namely, that while in the prophet the theoretical and practical virtues lie united, in the rest of humankind they lie fragmented. So that human perfection is found in the union of the virtues that no one person can achieve—no individual human can achieve true happiness alone. As Farabi himself puts it: “An isolated individual cannot achieve all the perfections by himself and without the aid of many other individuals. It is the innate disposition of every man to join another human being or other men in the labour he ought to perform: this is the condition of every single man” (al-Farabi, Attainment of Happiness, 23).



    Al-Farabi. The Attainment of Happiness—Taḥṣīl al-saʿādah. Translated by M. Mahdi, 2001, Alfarabi: Philosophy of Plato and Aristotle. Ithaca: Cornell University Press.

Miriam Galston


Absolute Certainty and Human Understanding

In this compact book, Anthony Booth argues that Alfarabi, and perhaps other medieval philosophers writing in Arabic, collectively known as the falāsifa, were not utopian thinkers. Alfarabi, Booth says, believed that throughout history, perfect certainty has been attained only by prophets.1 All other individuals, including philosophers,2 can obtain at most fallible certainty. For Booth, this means that Alfarabi’s theory is an example of what he calls “Moderate Evidentialism,” which has two key characteristics: (1) it is a form of knowledge that is supported by evidence and (2) at the same time, what is known could be incorrect because the evidence or reasons it relies upon are not infallible (19–22). Booth contrasts Moderate Evidentialism both with “Evidentialism,” according to which knowledge can be attained with perfect certainty based upon epistemic or scientific evidence (see 5, 20), and Anti-Evidentialism, namely, the view that all knowledge is ultimately dependent upon God’s will.3

For Booth, one implication of the hypothesis that some of the great falāsifa believed that the certainty non-prophetic humans can at best attain will be “forever a grade below” prophetic understanding (61) is the circumstance that those who today claim absolute certainty for their own beliefs are mistaken about the degree of certainty that is possible for humans other than prophets to have. Thus, the teachings of the moderate evidentialist falāsifa undermine the contention of contemporary religious extremists that their interpretation of Islam, and only their interpretation, is absolutely certain and that all other interpretations are heresy, deserving of eradication. However correct Booth’s inference may be in theory, it is doubtful that, in practice, the extremists who could benefit from his insights would be capable of appreciating and learning from them.

The reason Booth gives for claiming that only the prophet can attain absolute certainty4 is that only in a prophet are the theoretical and practical virtues united (66, 79). This is the case because the prophet’s faculty of imagination is superior to that of the rest of mankind.5 Booth’s assertion is not, however, consistent with the fact that Alfarabi portrays the union of theoretical and practical perfection in The Political Regime without mentioning a “prophet” or “prophecy.”6 In fact, neither “prophecy” nor “prophet” is mentioned anywhere in The Political Regime, even though the book’s depiction of the universe, human life, rulership, and political communities is frequently parallel to the portrayals of those things in The Virtuous City, where prophecy and the prophet’s imagination are central concepts.

According to The Political Regime, the “first ruler without qualification” (al-ra’īs al-awwal ʽalā al-iṭlāq) attains both theoretical and practical perfection7 and, as a result, does not need to be ruled by anyone and is capable of guiding all others to happiness to the extent possible for each.8 Thus, the first ruler without qualification in that book appears to be a philosopher-king.9 Alfarabi adds that “this is the one of whom it ought to be said that he receives revelation,”10 suggesting a contrast with the one who typically is said to have received revelation, i.e., the prophet. In The Virtuous City, in contrast, the first or ideal ruler is called a prophet, and what makes him a prophet is said to be the revelation that comes to his imagination after he has become a philosopher and possessor of practical wisdom.11 In other words, both books portray a first or ideal ruler, but the portraits differ in that in The Virtuous City, the first ruler is called a prophet and has theoretical and practical perfection, which includes a superior imagination, while in The Political Regime the first ruler is not called a prophet and has achieved theoretical and practical perfection with no mention of imagination.

Booth concludes from the account in The Virtuous City that only the prophet is capable of absolute certainty, since it is the prophet’s superior imagination that is expressly said to enable him to attain the practical perfection that must accompany theoretical perfection for absolute certainty to be achieved. In particular, according to Booth, the prophet’s superior faculty of imagination is what enables the prophet to know “how to transform the ideal into the real” (66, also 54), which is the culmination of practical perfection. Alfarabi does say in The Virtuous City that the prophet is the man who grasps every action by which it is possible to attain happiness.12 This may be the text that underlies Booth’s statement that it is the prophet’s superior imagination that enables him to transform “the ideal into the real.”13 Yet Alfarabi also says, in The Political Regime, where prophecy is not mentioned, that the first ruler without qualification is able “to determine, define, and direct the activities toward happiness” because of the perfection of his rational faculty.14 In other words, based upon the theoretical and practical capacities he attributes to the respective first rulers in the two works, Alfarabi appears to recognize two paths to absolute certainty, one prophetic and one non-prophetic. It is thus not surprising that in his work The Attainment of Happiness, Alfarabi characterizes the first ruler as a philosopher, prince, lawmaker, and imam—but not a prophet.15

The preceding does not, however, undermine the main thesis that for everyone beside the two first rulers, absolute certainty is not obtainable. In fact, Alfarabi gives some indications that Booth’s larger thesis is true. For example, in the Selected Aphorisms, Alfarabi states that practical reason encompasses both (1) practical intellect (al-ʽaql al-ʽamalī) that grasps the premises upon which practical wisdom or prudence (taʽaqqul, phronēsis) is based and (2) practical wisdom, which actually engages in deliberation about the means to obtain the ends sought.16 He says that the practical intellect that attains the premises of practical reasoning acquires its knowledge through observation and experience.17 Significantly, Alfarabi adds that practical intellect becomes intellect in act through experience and that it “increases along with the increase in experiences with each of the years of a human being’s life.”18 This statement implies that the foundations of practical knowledge are in principle not completely attainable in the course of a lifetime, since in practical life, one can always have additional experiences that alter what one “knows,” thereby increasing one’s practical understanding.

On the theoretical side, at the end of his book known as The Philosophy of Aristotle, Alfarabi portrays Aristotle’s metaphysical inquiries as incomplete.19 This is surprising because the title of the book is “The Philosophy of Aristotle, the Parts of His Philosophy, the Ranks of Order of Its Parts, the Position from Which He Started and the One He Reached.” In other words, it purports to be a comprehensive account of Aristotle’s philosophy. Lest the reader imagine that Alfarabi was tacitly contrasting the incompleteness of Aristotle’s philosophy to his own or his peers’ superior situation, he states in the final paragraph of the work that in his own time, they lack perfect natural science because “we do not possess metaphysical science. Therefore, philosophy must necessarily come into being in every man in the way possible for him.”20 Although he does not elaborate, these words indicate that Alfarabi believes that he, his peers, Aristotle, and presumably others have attained only an incomplete, thus imperfect, grasp of what they seek to know.

Booth’s important essay thus captures a foundational insight rarely associated with Alfarabi, namely, that what is available to most of us are beliefs that “are secure but not absolute” (49). It follows that our moral obligation, the ethics of our belief, is to “aim to have beliefs that are as justified as possible” (58).



Selected Aphorisms. Fuṣūl Muntazaʽah, edited with an introduction and notes by Fauzi Najjar as Alfarabi’s Selected Aphorisms (Beirut: Dar el-Mashreq, 1971). English translation by Charles E. Butterworth in Alfarabi The Political Writings: Selected Aphorisms and Other Texts (Ithaca & London: Cornell University Press, 2001), 11–67. The English translation references the pages of Najjar’s edition in brackets and follows that edition’s paragraph numbering.

The Attainment of Happiness Taḥṣīl al-saʽādah, edited by Jafir al-Yasin (Beirut: Al-Andaloss, 1981). English translation by Muhsin Mahdi in Alfarabi, Philosophy of Plato and Aristotle (rev. ed., Ithaca: Cornell University Press, 2001), 13–50.

The Philosophy of Aristotle: Falsafat Arisṭūṭālīs, edited by Muhsin Mahdi (Beirut: Dār Majillat Shi’r, 1961). English translation by Muhsin Mahdi in Alfarabi, Philosophy of Plato and Aristotle (rev. ed., Ithaca: Cornell University Press, 2001), 71–130.

The Political Regime. Edited by Fauzi Najjar as Al-Fārābī’s The Political Regime (Al-Siyāsa al-Madaniyya also known as the treatise on the principles of beings) (Beirut: Imprimerie Catholique, 1964). English translation by Charles E. Butterworth, Alfarabi The Political Writings II: “Political Regime” and “Summary of Plato’s Laws” (Ithaca: Cornell University Press, 2015), 29–94.

The Virtuous City. Richard Walzer, Al-Fārābī on the Perfect State. Abu Nasr al-Fārābī’s Mabādi’ Ārā’ Ahl al-Madīna al-Fādila (Oxford: Clarendon, 1985). This work contains both the Arabic text and an English translation on facing pages.

  1. Anthony Robert Booth, Islamic Philosophy and the Ethics of Belief (Palgrave Macmillan, 2016), 19–20, 24, 58, 74, 79. All page references are to this book unless otherwise specified.

  2. However, prophets are necessarily also philosophers (42).

  3. See 25–31, 42 (discussing Anti-Evidentialism and Moderate Anti-Evidentialism).

  4. Sometimes Booth uses “absolute certainty” (see 44, 45, 49, 55, 57, 58) and sometimes “proper certainty” (see 19, 20, 21, 24, 41, 43, 77).

  5. See 54, 66. Booth emphasizes that for Avicenna, unlike Alfarabi, the prophet’s imagination can be a source of new knowledge that ordinary humans cannot acquire (67).

  6. Political Regime 79:3–80:4 (Butterworth tr., 68–69) and the index to Arabic edition.

  7. The first ruler attains the sciences and cognitions in actuality and also grasps everything that must be done, including the means to achieve his ends (Political Regime 79:3–8; Butterworth tr., 68–69).

  8. Political Regime 79:3–8 (Butterworth tr., 68–69).

  9. Alfarabi notes that “the Ancients” considered the first ruler without qualification to be the king in truth (Political Regime 79:12, Butterworth tr., 69).

  10. Political Regime 79:12–13 (Butterworth tr., 69).

  11. Virtuous City 244:7–14.

  12. Virtuous City 246:1.

  13. See 54, although Booth does not mention the work in this passage.

  14. See Political Regime 79:7–8, 15–17 (Butterworth tr. 69). The descriptions in the two works are very similar, linking the ruler’s ability to grasp what leads to happiness to his intellect’s contact with the active intellect.

  15. Booth notes that Alfarabi fails to say that the ideal ruler described in the Attainment of Happiness is a prophet, but he assumes that the person is a prophet despite the omission. See 75n7. It is unclear why Booth believes that, were Alfarabi to have added “prophet,” it would be heretical. In The Virtuous City (244), for example, prophecy is depicted as coming to someone who is a philosopher and man of practical wisdom.

  16. Selected Aphorisms nos. 38–39 (Butterworth tr., 31).

  17. Selected Aphorisms no. 38 (Butterworth tr., 31).

  18. Selected Aphorisms no. 38 (Butterworth tr., 31).

  19. See Philosophy of Aristotle 59:2–3 (Mahdi tr., 71), which suggests that Alfarabi viewed Aristotle’s investigation of metaphysics as ongoing. Since Alfarabi also states that for Aristotle, natural and human science are inconclusive until the inquiry into the beings beyond the natural beings is complete, he seems to be suggesting that natural and human knowledge were tentative for Aristotle.

  20. Philosophy of Aristotle 132:15–133:3 (Mahdi tr., 130).

  • Anthony Booth


    Reply to Galston

    I am a big admirer of Miriam Galston’s work, and I rate her book Politics and Excellence: The Political Philosophy of Alfarabi among the best books out there on al-Farabi’s political philosophy. So I feel very honoured that she has taken the time to read my work and to comment on it here. Her critique is based around my putative failure to account for the fact that especially in al-Farabi’s The Political Regime we find no real mention of prophets or prophecy, so that if we take his oeuvre in toto we see that he “appears to recognize two paths to absolute certainty, one prophetic and one non-prophetic.” I will focus this reply then on attempting to formulate my alternative reading of The Political Regime more explicitly.

    However, before I do so, I would like to clear up an issue as to what I meant the thesis of Islamic Moderate Evidentialism to denote. I think the latter differs from what I think of as Western Moderate Evidentialism in that it moderates the Evidentialist tenet (believe that p only if you have good evidence for p) by restricting who the tenet applies to—namely, an epistemic elite. In Western Moderate Evidentialism this is done by restricting the scope of the propositions the Evidentialist tenet applies to—so that for certain propositions, such as those where our evidence is inconclusive, we can believe for non-epistemic reasons (I take Aquinas to endorse something close to this view). I take all of al-Farabi, Averroes, and Avicenna to endorse Islamic Moderate Evidentialism, but differ as to who they think is a member of the elite class. In my book I tried to argue for an interpretation of al-Farabi where he thinks that only prophets are members, and can alone attain absolute certainty. For all of us ordinary humans we can believe for non-epistemic reasons and this is because we are unable to achieve absolute certainty. With this in mind we can see that there is a further sense that al-Farabi’s Evidentialism is “moderate” (as Galston notes), and as I tried to suggest in my book this may give us some tools for understanding extremism from within an Islamic perspective. Galston in her reply gives me some further textual evidence that may support this thesis, and I thank her wholeheartedly for it. I fear that Galston may well be right that “it is doubtful that, in practice, the extremists who could benefit from his insights would be capable of appreciating and learning from them,” but I also hope it is progress to begin to see a new way of conceptualising extremism from within Islamic thought. What’s then at stake here, as in my exchange with Sabeen Ahmed, is how Islamic is al-Farabi’s thought meant to be.

    I agree with Galston that in The Political Regime al-Farabi does not mention the word “prophet,” but I disagree that his idealised “First Ruler” is meant to be a “Philosopher King.” She quotes an important passage to support her interpretation of this ruler: “This is the one of whom it ought to be said that he receives revelation” (al-Farabi, Political Regime, sect. 80). And she says that this suggests “a contrast with the one who is typically said to have received revelation, i.e. the prophet.” I think we can read this statement differently, however, when we see the quotation in full:

    This human being is the king in truth according to the ancients, and he is the one of whom it ought to be said that he received revelation.

    Here I think we can read al-Farabi instead to be criticising the ancients for thinking that the ruler must be a Philosopher-king (“a king in truth”) and not a prophet (someone who not only has the requisite knowledge of human nature, but has also attained rhetorical and dialectical perfection such that he can be a good “instructor” as he puts it elsewhere in The Political Regime). Later in the same section, al-Farabi says:

    For a human being receives revelation only when he obtains this rank, and that is when there remains no intermediary between him and the active intellect. . . . Then [my italics] there emanates from the active intellect to the passive intellect the faculty by which is able to seize on the definition of things and actions and direct them toward happiness. This emanation proceeding from the active intellect to the passive intellect by the intermediary of the acquired intellect is revelation.

    While it is true that he here is not as explicit about the role of prophetic imagination as he is in his The Perfect State, I think we can read al-Farabi as saying that for the ideal ruler to have the requisite practical virtues an emanation must occur after she has become an acquired intellect. And of this emanation, al-Farabi had previously written in The Political Regime:

    When the rational part of the soul is perfected and becomes an intellect in actuality, it closely resembles the separate things. Yet it procures the perfection of existence, becoming actual, splendour, radiance, and beauty not just by intellecting the things above it in rank, but by intellecting the things that are beneath it in rank as well and by greatly magnifying the multiplicity in what is made substantial by means of it. When it becomes completely separated from all the parts of the soul apart from it, its existence also comes to be limited to itself alone and does not emanate to anything apart from it. (sect. 19, my italics)

    So putting the two passages above together, we get: the best ruler receives their capacity to rule from an emanation via the acquired intellect (this is revelation), and this emanation can only happen if the rational intellect has not been completely separated from the other parts of the soul (including the imaginative faculty). The imagination is important then, since without it there would be no material for the relevant emanation to give form to, and the better the material the greater the “magnifying the multiplicity of what is made substantial” will be (“and the acquired intellect is similar to material and a subject for the active intellect,” sect. 80).

    Finally, take the last two sentences of section 80:

    The rulership of this human being is the first rulership, and the rest of the human rulerships are subsequent to this one and proceed from it. And that is evident.

    Al-Farabi may have meant here that given how he has defined rulership that his conclusion is thereby “evident.” But he may have meant that the historical progress of the Caliphate form Muhammad to the Rashidūn evidences his thesis. At any rate, it seems clear to me that both in The Political Regime as well as in The Perfect State and The Attainment of Happiness al-Farabi is very careful to ensure that there is nothing in his political philosophy that would contradict the Islamic historical narrative.



    Al-Farabi. The Political Regime (Al-Siyāsah al-Madanīyyah). Translated by Charles Butterworth, 2001, in Butterworth, ed., Alfarabi: The Political Writings, vol. 2.

    Galston, M. 1990: Politics and Excellence: The Political Philosophy of Alfarabi. Princeton: Princeton University Press.

Ethan Mills


Non-Prophet Management and Therapy for Anti-Skeptics

Cross-Cultural Thoughts on Booth’s Islamic Philosophy and the Ethics of Belief

Anthony Robert Booth’s Islamic Philosophy and the Ethics of Belief is a comparative project that forges connections between medieval Islamic philosophy and contemporary analytic epistemology. A similar strategy has been used in my own field of classical Indian philosophy, most prominently by B. K. Matilal, who put contemporary analytic figures like Quine and Dummett into dialogue with classical Indian figures like Dignāga and Uddytotakara.1 This approach can be philosophically interesting, and it helps make Indian philosophy more visible within the discipline. Booth shows that a similar approach can yield fruits for Islamic philosophy.

My response will focus on Booth’s articulation of al-Farabi’s fallibilist anti-skepticism. I present two objections to al-Farabi inspired by Hellenistic and ancient Roman philosophy, followed by two responses inspired by classical Indian philosophers.

Al-Farabi’s Fallibilist Anti-Skepticism

After a critical engagement with Deborah Black’s interpretation of al-Farabi, Booth argues that al-Farabi’s position with regard to the ethics of belief is Moderate Evidentialism. Prophets ought to hold a belief if and only if they have epistemic reasons while non-prophets may in some circumstances believe on the basis of non-epistemic reasons (42–43).

Booth translates the Arabic ‘ilm as “epistemic justification” rather than “knowledge,” because ‘ilm is gradable and many philosophers claim knowledge is not (44–45). He then lists six conditions for absolute certainty. Prophets meet all six conditions, while non-prophets may meet fewer—someone meeting three conditions is more epistemically justified than someone meeting two, etc.

Booth calls these AFC2.2

1* S believes that p.

2* S believes that p for epistemic reason.

3* S (infallibly) believes that S believes that p for epistemic reason [S has taken cognizance of her reasons for belief].

4* S (infallibly) believes that it is impossible for there to be no epistemic reason for her to believe that p.

5* S (infallibly) believes that there can be no time at which there is no epistemic reason for her to believe that p.

6* Conditions 1*–5* hold essentially, not accidentally. (Booth 2016, 45)3[/NL]

Booth claims this provides a fallibilist response to skepticism: “Beliefs can be less than perfectly justified, and so less than fully certain, but nonetheless admit of a certain degree of justification” (Booth 2016, 58). Non-prophets in certain contexts can claim their beliefs are justified enough insofar as they meet at least conditions 1*–2*.4

Two Objections

My first objection is inspired by Augustine’s Against the Academicians. Augustine criticizes the notion of “truthlike impressions” defended by Cicero and Carneades as an answer to the inconsistency objection (skeptics claim to know that knowledge is impossible) and the inactivity (apraxia) objection (skeptics cannot live according to skeptical principles).5 Academics said they have a truthlike impression that knowledge is impossible and they act on truthlike impressions.

Augustine’s criticism is simple yet clever: if one is never certain that one has an impression of the truth, how will one ever recognize that an impression is like the truth? It would be like claiming that someone’s brother looks like his father when one has never met the father (Augustine 1995, 41).6

Turning to al-Farabi: Since non-prophets can’t attain the absolute certainty of prophets (they can’t meet condition 6*), how can non-prophets have a basis for comparing their own beliefs, even those meeting conditions 1*–5*, with those of prophets to assign any level of certainty at all? In the language of modern probability that Booth uses later (84–85), how can one calculate the probability of one’s belief as .7 or .8 when one has no idea what 1.0 looks like?7

Perhaps we use prophets as guides. This generates a second objection: how can we be sure that a particular person is a prophet? Al-Farabi claims God guarantees that prophets possess perfect persuasion skills; if we fail to be convinced, it’s our own fault (60). But this creates a skeptical scenario: because we lack condition 6*, which is supposed to rule out skeptical scenarios, we can’t tell the difference between a convincing false prophet and a convincing real one. Booth argues against al-Ghazali’s tests and Averroes’s inconclusive methods (61). There is a gap between a prophet’s rhetoric and epistemic certainty that al-Farabi closes with divine help, but this gap is impossibly wide for non-prophets.

Two Classical Indian Responses

The Indian Buddhist philosopher Vasubandhu argues—1,200 years before Descartes—that dreams and hallucinations demonstrate a surprising fact about our epistemic situation. Here is the main argument of his Twenty Verses in the form of a classical Indian inference (anumāna):

  1. Conclusion: This world is cognition-only.
  2. Because of the appearance of nonexistent objects.
  3. Whatever possesses the appearance of nonexistent objects is cognition-only, as in hallucinations and dreams.

Vasubandhu’s arguments in this text are similar to modern external-world external skepticism in that external objects are not the direct objects of perception, whether external objects exist or not (Mills 2016b).

Vasubandhu’s diagnosis of our ignorance is that our minds overlay our experience with a conceptual imputation of subject and object. Buddhas, however, have cured themselves of subject-object dualism. As a non-Buddha, Vasubandhu humbly does not speculate about what reality is truly like. Only a Buddha could know.8 While al-Farabi claims prophets know because they possess imagination (Booth 2016, 54), Buddhas are trustworthy because they lack imagination.9

Vasubandhu does not answer the question of how we can tell who’s a real Buddha. However, Vasubandhu’s view has parsimonious benefits (“lightness” in Indian terminology). Buddhists in India vociferously argued against anything like an Abrahamic omnipotent creator.10 Vasubandhu’s account is simpler than al-Farabi’s in at least one way: it does not require God to make it work. While Buddhist atheism is a non-starter for al-Farabi, a simpler account of non-prophets’ errors might help him respond to my objections.

A second response comes from Indian philosophers more like Pyrrhonian skeptics. Booth mentions Neo-Pyrrhonism (84), but let’s turn instead to Paleo-Pyrrhonism.11 Sextus Empiricus says that skeptics follow appearances when it comes to practical matters.12 If you go in for philosophy’s attempt at a deeper explanation of knowledge, that way madness lies (or so it seems—let’s not make any rash statements). A similar attitude was exemplified in classical India by Nāgārjuna, Jayarāśi, and Śrī Harṣa.

While these three differ in various ways,13 each offers extensive critiques of philosophical currents of his day as therapy for intellectuals, often relying on prasaṅgas, arguments aiming to show that opponents’ views contradict themselves.14 Furthermore, none of these skeptics thinks his devastating critiques are devastating for everyday life.15 Pursuing philosophical justification is the problem.16 While Nāgārjuna and Śrī Harṣa have religious motivations,17 Jayarāśi’s point as an irreligious Cārvāka is that once you get over philosophical squabbling, you can fully enjoy a worldly life.18

Hellenistic and Indian skeptics did not focus on what we call the problem of the external world,19 and modern skepticism is a theoretical conclusion that arises within epistemology while ancient skepticism is generally a therapeutic repudiation of epistemology.20 Risking anachronism, however, I think ancient skeptics would find the project of “answering the skeptic” to be doomed and the modern skeptic (who is a phantom place holder in philosophers’ imaginations, anyway) to be a negative dogmatist: claiming that knowledge is not possible is as dogmatic as claiming it is. What if ancient skeptics show us that we could learn to be okay with having no answer for the modern skeptic? What if modern skepticism is neither demonstrably wrong, nor necessarily troubling?

While I lack the expertise to ascertain whether al-Ghazali or other Sufis make similar moves, I wonder if quietist skepticism of Indian, Hellenistic, or Islamic varieties might make for interesting—if a bit outré—responses to modern skeptics and anti-skeptics alike.

Perhaps a larger lesson from cross-cultural philosophy is that for those not lucky enough to be prophets or Buddhas, philosophy has always been a messy, uncertain business.



Aikin, Scott, and Thomas Dabay. Forthcoming. The Mystery of Skepticism. Edited by Kevin McCain and Ted Poston.

Augustine. 1995. Against the Academicians and the Teacher. Translated by Peter King. Indianapolis: Hackett.

Booth, Anthony Robert. 2016. Islamic Philosophy and the Ethics of Belief. London: Palgrave Macmillan.

Cicero. 2006. On Academic Scepticism. Translated by Charles Brittain. Indianapolis: Hackett.

Fine, Gail. 2003. “Sextus and External World Skepticism.” Oxford Studies in Ancient Philosophy 24:341–85.

Fogelin, Robert J. 1994. Pyrrhonian Reflections on Knowledge and Justification. Oxford: Oxford University Press.

Granoff, Phyllis. 1978. Philosophy and Argument in Late Vedānta: Śrī Harṣa’s Khaṇḍanakhaṇḍakhādhya. Boston: Reidel.

Hayes, Richard. 1988. “Principled Atheism in the Buddhist Scholastic Tradition.” Journal of Indian Philosophy 16:5–28.

Jayarāśi. 1994. Tattvopaplavasiṃha. Edited and Translated by Eli Franco. In Perception, Knowledge and Disbelief: A Study of Jayarāśi’s Scepticism. 2nd ed. Delhi: Motilal Banarsidass.

Matilal, Bimal Krishna. 1986. Perception: An Essay on Classical Indian Theories of Knowledge. Oxford: Clarendon.

Mills, Ethan. 2016a. “Nāgārjuna’s Pañcakoṭi, Agrippa’s Trilemma, and the Uses of Skepticism.” Comparative Philosophy 7:44–66.

———. 2016b. “External-World Skepticism in Classical India: The Case of Vasubandhu.” International Journal for the Study of Skepticism 6:1–26.

Nāgārjuna. 2013. Nāgārjuna’s Middle Way: Mūlamadhyamakakārikā. Translated by Mark Siderits and Shōryu Katsura. Boston: Wisdom.

Phillips, Stephen H. 1995. Classical Indian Metaphysics: Refutations of Realism and the Emergence of “New Logic. Chicago: Open Court.

Ram-Prasad, Chakravarthi. 2002. Advaita Epistemology and Metaphysics: An Outline of Indian Non-Realism. New York: Routledge.

Sextus Empiricus. 2000. Outlines of Scepticism. Translated by Julia Annas and Jonathan Barnes. Cambridge: Cambridge University Press.

Śrī Harṣa. 1986. The Khaṇḍanakhaṇḍakhādya of Shri-Harṣa: An English Translation. Translated by Ganganatha Jha. Delhi: Sri Satguru.

Thorsrud, Harald. 2009. Ancient Scepticism. Berkeley: University of California Press.

Vasubandhu. 2005. “Viṃśikāvṛtti (Twenty Verses and Commentary). In Seven Works of Vasubandhu, edited by Stefan Anacker, 413–21. Delhi: Motilal Banarsidass.

  1. I recently coedited, along with Prasanta Bandyopadhyay, an issue of the APA Newsletter on Asian and Asian-American Philosophers and Philosophies (Fall 2017) focused on the life and legacy of Matilal (1935–1991). See also Matilal 1986 for more on his approach to comparative philosophy.

  2. I assume this stands for “al-Farabi conditions.” Booth’s list is distinguished from Black’s alternative list, which is called AFC1.

  3. Booth claims that these conditions rule out epistemic luck of both the evidential and veritic varieties (49).

  4. Booth also compares this to epistemic contextualism on pp. 57–58.

  5. See Augustine 1995 and Cicero 2006. A version of Augustine’s argument is also mentioned by Cicero himself in Academica 2.36 (Cicero 2006, 23). This sort of argument is also discussed in Aikin and Dabay forthcoming.

  6. This objection appears at 2.7.16 of Against the Academicians. Augustine later claims that the Academics do (secretly) apprehend the truth—their skepticism is a sham (Against the Academicians 3.20.43; Augustine 1995, 92).

  7. Furthermore, it’s difficult to explain how we could be justified in believing that we’re in conditions 2*–5* (granting that 1* is obvious: one incorrigibly knows that one believes p through introspection.) Maybe, pace contextualism, we have lower standards that constitute justification for conditions 2*–5*. However, once we raise the question of how we are justified in believing that we possess this justification, there is a problem. Say I believe that al-Farabi died in 950 CE, meeting conditions 1*–5* (I read it in Booth’s book, after all). But how can I be justified in believing I’m in conditions 2*–5*? Given Booth’s reluctance to attribute a thoroughly externalist epistemology to al-Farabi (54–57), it’s not enough that my belief has the right causal history. Conditions 3*–5* seem like internalist conditions. Booth says the importance of condition 6* is that it rules out skeptical scenarios and epistemic luck.

  8. This paragraph is a paraphrase of Vasubandhu’s Twenty Verses 21–22. In Mills 2016b, I argue that this passage demonstrates an invitation to skepticism on Vasubandhu’s part.

  9. Of course, the Sanskrit and Arabic words being translated as “imagination” may have different connotations. In Sanskrit, imagination (kalpanā) has largely negative error-producing connotations, especially in Buddhist contexts.

  10. Few Indian philosophers proposed such a being outside of the Nyāya school. See Hayes 1988 for a solid treatment of Buddhist atheism in classical India.

  11. It’s not entirely clear why Booth mentions Neo-Pyrrhonism. Perhaps he’s thinking of the work of Robert Fogelin (e.g., Fogelin 1994).

  12. See Outlines of Pyrrhonism 1.13 and 1.19–24 (Sextus Empiricus 2000, 6, 8–9).

  13. Nāgārjuna (c. 200) is a Mahāyāna Buddhist, Jayarāśi (c. 770–830) is an irreligious Cārvāka, and Śrī Harṣa (c. 1125–1180) is a Brahmanical Advaita Vedāntin.

  14. A prasaṅga argument is not exactly the same as a reductio ad absurdum because it relies wholly on the opponents’ suppositions and a prasaṅga argument merely refutes p, but does not conclude by asserting not-p. The negation is what Indian philosophers call a prasajya negation, which Matilal has compared to Searle’s “illocutionary negation” (Matilal 1986).

  15. The Sanskrit for everyday practice—vyvahāra—has an etymology having to do with business transactions. I like to translate it with American idioms like “good enough for government work” or “close enough for horseshoes and hand grenades.”

  16. This is not, however, a form of fallibilism or contextualism insofar as these skeptics neither have nor desire any theory about fallibilist justification, context-dependent truth-conditions for knowledge ascriptions, and the like. Classical Indian skeptics would most likely consider these theories to be just as flawed as the infallibilist and invariantist theories they aim to replace.

  17. Nāgārjuna is developing an even more ancient tradition of Buddhist quietism, according to which the aim of engaging in philosophy is to reach a state of inner-quiet beyond the mental hubbub of disputation. Śrī Harṣa is destroying the bases of realist philosophy to reveal the possibility of a mystical apprehension of non-dual idealism, although intriguingly he does not straightforwardly argue in favor of idealism.

  18. He ends his text, Tattvopaplavasiṃha (The Lion That Destroys All Principles), as follows: “When, in this way, the principles are entirely destroyed, all everyday practices (vyavahāra) are made delightful, because they are not deliberated.” (This translation is my own. See also Jayarāśi 1994.)

  19. For discussion on whether Sextus discussed the external world, see Fine 2003 and Thorsrud 2009, 182–83. Śrī Harṣa’s critique of the die-hard realism of the Nyāya school could also be seen as something closer to the problem of the external world. See Granoff 1978, Ram-Prasad 2002, and Phillips 1995.

  20. See Mills 2016a for more on how I characterize ancient versus modern skepticism. While some Academic skeptics come closer to epistemological theorizing (e.g., the notion of truthlike impressions, etc.), they nonetheless always have practical aims in mind. Cicero, for example, claims that Academics will be “freer and less constrained” than dogmatists (Cicero 2006, 6).

  • Anthony Booth


    Reply to Mills

    As Ethan Mills begins his piece by saying, part of what I was trying to do in Islamic Philosophy and the Ethics of Belief was to bring contemporary analytic epistemology “into dialogue with” the work of certain figures in medieval Islamic philosophy. Mills raises some important objections to al-Farabi’s “response” to the sceptical challenge, as I presented it might go, and does so—congruently with the spirit of my book—partly through the prism of a tradition I did not engage with: classical Indian philosophy. Given the fruits I think that a comparative study between analytic epistemology and Islamic philosophy can yield, I hope that even more expansive dialogue between traditions will be even more fertile terrain. Before I begin addressing some of Mills’s concerns, let me first, however, issue some clarificatory words about what I take my “comparative project” to comprise. My aim was not simply to compare Islamic philosophy with analytic philosophy, and find points of similarity and difference, for no other intellectual end. Rather, I wanted to do philosophy with the historical figures of Islamic philosophy using the intellectual resources that I happen to be most familiar with. I feel that engaging wholly from the point of view of history, and thus failing to engage philosophically, with the works of medieval Islamic philosophy is to tacitly endorse an imperialist, orientalist discourse toward the subject. It is to treat the works of the Islamic philosophers as mere items of curious exotica, such that the correct tools for studying them are primarily philological and sociohistorical, not actually philosophical. My aim instead is to learn philosophical lessons by engaging with these works, and I cannot do so unless I approach them from within my own philosophical background. My guess is that I am on the same page as Mills here, however, so enough said.

    Mills raises some important challenges to al-Farabi’s “response” to “modern” external world scepticism, and begins to articulate an alternative “quietist” way to respond by way of a challenge—asking whether there is a similar intellectual impulse underscoring both this alternative and the thought of al-Farabi’s Sufi critic al-Ghazali, as well as that of other Sufi thinkers. He attributes this quietist response to “Hellenistic and Indian skeptics” and in particular Indian thinkers such as Jayarāśi whose point, claims Mills, “as an irreligious Cārvāka is that once you get over philosophical squabbling, you can fully enjoy a worldly life.” And Vasubandhu’s idea that “our minds overlay our experience with a conceptual imputation of subject and object. Buddhas, however, have cured themselves of subject-object dualism.” So that the overall stance toward external world scepticism is one where we have “learned to be ok with having no answer for the modern skeptic” and where to take modern scepticism to be “neither demonstrably wrong, nor necessarily troubling.” In response to Mills’s question, I think that this fascinating take on external world scepticism is one that certainly, at least to some extent, can be found in Sufi thought. But it is also not as divergent to al-Farabi’s own position as perhaps Mills intimates. Let me explain.

    Mills sometimes writes as if I was wanted to make al-Farabi’s response to the sceptic to be one that is in accord with contextualist approaches in modern analytic epistemology. That was not quite what I meant. I take al-Farabi instead to be answering a different question from the traditional question of modern epistemology: what is knowledge? That is, I take him to be not at all concerned about what is knowledge but rather to be concerned about the question of what is justified belief—and I take the grammar of the word ʿilm to partly corroborate my interpretation. It is true that modern epistemologists have taken there to be an intimate connection between the two notions, since they have thought justified belief to be a necessary condition of propositional knowledge. But I think this is a mistake (cf. Booth 2017) and that we cannot assume al-Farabi held there to be such a link, since he was not really addressing the question of what is knowledge. Now, as Mills mentions, I think that al-Farabi held that there can be various degrees of justified belief, with the attaining of absolute certainty at the top of the scale. I think that al-Farabi thinks two important things about this top-scale rate of certainty: (i) that only prophets can achieve it; (ii) it is a composite of both practical and theoretical perfection. (ii) is a corollary of very stringent K-K requirements, that I think al-Farabi develops from Aristotle’s idea that syllogisms that constitute proper proof are ones whose middle term is explanatory. Thus for al-Farabi there is a principled link between proper certainty and perfect rhetorical ability—between the esoteric and the exoteric. This underscores what I called his version of Moderate Evidentialism: where Evidentialism only applies to an elite, and where for the non-elite there can be non-epistemic reasons for belief. Mills wonders whether for those of us who cannot attain proper certainty can we “tell the difference between a convincing false prophet and a convincing real one”? My response is that, as per al-Farabi’s Moderate Evidentialism, ascertaining this difference is not the cognitive task of the ordinary believer—but rather the task of the prophet, whose rhetorical and practical skills are perfected, such that they will give us non-epistemic reasons to believe them. Putting this last thought together with the claim that al-Farabi was interested in the conditions of justified belief, not knowledge, yields a picture where al-Farabi’s thinks that our ordinary stance toward external world scepticism is one precisely where we are enjoined to look to the practical and the worldly in the justification of our beliefs. Under this picture, seeking sceptic-defying justification for our beliefs would look like some sort of a category mistake at best, and a waste of time at worst.

    Once we have disabled the force of the objection that the ordinary person cannot tell apart convincing false prophets from convincing real ones, we also arrive at the answer to the objection Mills raises from Augustine; viz. “In the language of modern probability that Booth uses later (84–85), how can one calculate the probability of one’s belief as .7 or .8 when one has no idea what 1.0 looks like?” The answer I think, as Mills anticipates, is that we use “prophets as guides.” Differently put, the prophet’s state of perfect certainty is what 1.0 looks like to us, and so it looks like something we are unable to achieve. But precisely what makes it so hard to achieve creates the principled link between the prophets’ certainty and their rhetorical ability, such that the cognitive task of determining true prophets we are a witness to is one we have generously been spared. Does this mean that al-Farabi’s response to the Sceptic requires, as Mills puts it, “God to make it work”? That will depend, I think, on how far we are prepared to allow al-Farabi’s ideal prophet, whose perfected state of certainty unifies the practical and theoretical, to be a regulative (and not constitutive) ideal.



    Booth, A. R. 2017: “Advice for Infallibilists: DIVORCE and RETREAT!” Synthese online first: