AUGUSTINE’S MASTER ARGUMENT FOR THE INCORPOREALITY OF THE MIND

In De Trinitate 10 , Augustine offers an argument that seemingly proceeds from certain premises about self-knowledge to the conclusion that the mind is incorporeal. Although the argument has sometimes been compared to later Cartesian arguments, it has received relatively little philosophical attention. In this paper, I offer a detailed analysis and original interpretation of Augustine’s argument and argue that it is not vulnerable to some of the main objections which have been raised against it. I go on to argue that while an important part of Augustine’s argument does face several hitherto neglected objections, Augustine’s ultimate case for the incorporeality of the mind is somewhat different and more successful than one might initially think.


I. INTRODUCTION
In book 10 of his De Trinitate, Augustine offers an argument that seemingly proceeds from certain premises about the mind's self-knowledge to the conclusion that the mind is incorporeal. Augustine's argument is directed against corporealist accounts of the mind (common among the leading Hellenistic schools, 1 late antique medical authorities, 2 and several early Christians) 3 and is distinctive among ancient and early medieval arguments for the incorporeality of the mind while bearing certain similarities to later Cartesian arguments (which it may have influenced) 4 and some modern anti-physicalist arguments. 5 However, despite its intrinsic interest and historical importance (Augustine played an important role in popularising the view that the mind and soul are incorporeal), Augustine's argument has attracted relatively little philosophical attention and several of its central aspects have not been adequately understood. In this paper, I carefully examine Augustine's case for the incorporeality of the mind in De Trinitate 10, propose an original interpretation of several of its central elements, clarify both its strengths and weaknesses, and argue that, when several aspects of Augustine's argument are appropriately appreciated, it is somewhat different and more successful than one might initially think.
To this end, I first clarify Augustine's views about the mind's self-knowledge and what is distinctive about it (Section II). It is often thought that a principal objection to Augustine's case for the incorporeality of the mind is that he has no warrant for thinking that the mind knows its essence. However, I argue that Augustine's claims are supported by certain views about the mind's acquaintance with its activities and certain (Neoplatonic) assumptions about the 'dynamic' or 'active' nature of the mind's essence. I then carefully examine Augustine's case for the incorporeality of the mind (Sections III and IV). One of Augustine's arguments appeals to the mind's grasp of its essence to establish its incorporeality. I clarify the argument and argue that while it is not vulnerable to the principal objection which has been raised against it, it does face other significant objections which have not hitherto been adequately appreciated (Section III). However, Augustine offers a further argument which appeals to the mind's representational powers (Section IV) and this argument, I suggest, addresses the objections faced by Augustine's prior argument and is dialectically effective against Augustine's principal corporealist opponents who must either abandon their corporealist views of the mind or else revise some of their views about representation and self-cognisance.

II. THE MIND'S SELF-KNOWLEDGE
It is often thought that Augustine's argument for the incorporeality of the mind or intellect (mens, i.e. the rational and best part of the soul, Trin. 10.5.7; 14.8.11; 15.7.11) in De Trinitate 10 takes as a central premise the claim that the mind knows its essence. 6 However, even if one were to grant that the mind knows itself in some distinctive manner, it is obscure why one should accept 4 Influence is difficult to securely trace but similarities have long been noted by followers and critics of Descartes alike (e.g. AT [Adam-Tannery 1956-7] 3: 247-9, 283-4, 543-4;7:197-8;cf. Gouhier 1924;Janowski 2004). 5 For example, Goff (2017: 106-32); cf. Lewis (1995). 6 For example, Matthews (1992: 40-1;2000: 141;2005: 45-6); Bermon (2001: 77ff); Sorabji (2006: 220); Brittain (2012a: 130-3). In what follows, 'De Trinitate' is abbreviated as 'Trin'. that the mind knows its essence. Insofar as the matter has been discussed, it has often been thought that this central claim is ungrounded in a manner which profoundly damages Augustine's overall argument. 7 I take this to be a mistake and, in what follows, will aim to show that Augustine does in fact have grounds for thinking that the mind knows its essence.
At the opening of De Trinitate 10, Augustine focuses on making the case that the mind must have some kind of grasp of itself. This, he thinks, is shown by the fact that it can inquire into itself and that inquiring into α has certain cognitive and conative requirements, i.e. it requires that one already have some kind of cognisance (notitia, notio) of α and certain conative attitudes directed towards α. 8 Given that the mind is always able to inquire into itself, it must therefore have some kind of prior grasp of itself (Trin. 10.3.5). While various distinct kinds of cognisance make inquiry possible, 9 Augustine argues that the mind's cognisance of itself is epistemically privileged and distinctive when compared to its cognisance of many other things (Trin. 10.2.4-4.6) and it seems that there are at least four important features of the mind's self-knowledge which deserve attention.
First, Augustine thinks the mind's self-knowledge is neither generic nor indirect (Trin. 10.2.4-3.5), but direct. Thus, Augustine notes that in attempting to inquire into things with which we are not acquainted, we often rely upon general conceptions of things with which we are acquainted, 10 or upon forming some representation(s) (imago, cf. phantasma, figmentum, fictas imagines) of the object of inquiry through imagination (Trin. 10.2.4). 11 However, the mind's cognisance of itself is prior to its cognisance of other minds and does not require cognising something else (Trin. 9.6.9; cf. Plotinus Enneads 5.1.5). That is to say, in cognising itself, the mind does not rely upon generic cognisance (which would require prior acquaintance with other minds, Trin. 9.3.3; 10.3.5) or upon testimony, imagination, or (defeasible) inference, as it does when inquiring into the mind of another. 12 In fact, the mind is always present (praesens) to itself in such a way that it does not need to rely upon any kind of conceptual representation of itself in order to cognise itself (Trin. 10.3.5; cf. Trin. 8.6.9). 13 The mind thus stands in some direct kind of epistemic relation to itself, which we would nowadays 7 For example, Matthews (2005: 46); Sorabji (2006: 220-1); Horn (2012: 213-4); Niederbacher (2014: 133-5); Nawar (2016: 33-4). Cf. Lloyd (1964: 189-90).
Downloaded from https://academic.oup.com/pq/advance-article/doi/10.1093/pq/pqab020/6246425 by guest on 20 July 2021 regard as a form of acquaintance or a certain kind of de re cognisance. While such cognisance requires that the agent be non-conceptually related to the object of cognisance, such cognisance may involve or be accompanied by having certain beliefs about the object of cognisance. 14 Secondly, Augustine aims to establish that the mind is not merely acquainted with some part of itself, but with the entirety of itself. In support of this claim, Augustine offers a brief argument (Trin. 10.4.6), 15 which we may call the Whole Knowledge Argument. Its kernel is as follows: (i) ∀x∀y (if x knows y, then the whole of x knows y); (ii) the mind knows itself * ; 16 (iii) the whole of the mind knows itself * ; (iv) the whole of the mind knows the whole of the mind.
While the Whole Knowledge Argument might initially seem puzzling, 17 it turns upon the thought that there are certain xs and certain ϕs such that if x ϕs, then the whole of x ϕs (i.e. there is no part of x which does not ϕ) and the reflexive nature of the relevant activity. 18 Like several later Platonists (e.g. Plotinus Enneads 5.3.5.1-7, 6.7-8; Porphyry Sententiae 44.12-16), 19 Augustine thinks this holds of certain activities of the mind because the mind is strongly unified in some suitable sense (e.g. Trin. 9.4.7; 10.7.9-10). Such a view was congenial to at least some of Augustine's corporealist opponents, most notably the Stoics, who also emphasised that the intellect (διανoία, e.g. Diogenes Laertius 7.110,157) 14 Discussions of non-conceptual thought in ancient philosophy have rarely been pellucid. Here I merely note that, following Russell (1912), one might suppose that acquaintance with x requires: (i) standing in a certain cognitive relation to x; and (ii) being aware of x in a nonconceptual manner. However, this is not to say that one's awareness of x or thoughts about x need to be exclusively or primarily non-conceptual. Being acquainted with x typically involves, requires, or has as a consequence having certain beliefs about x (cf. Grice 1941: 38ff;Russell 1912: 46;Shoemaker 1987: 102ff; for similar claims about de re belief, see Burge 1977).
15 'Then what shall we say? That the mind knows itself in part, and in part does not know itself (An quod ex parte se novit, ex parte non novit)? But it is absurd to claim that it does not know as a whole what it knows (non eam totam scire quod scit). I do not say that "it knows the whole [of itself]" (non dico: totum scit), but "what it knows, the whole [of it] knows" (quod scit, tota scit)... But it knows itself as knowing something, nor can it know anything unless the whole of it knows (Scit autem se aliquid scientem, nec potest quidquam scire nisi tota). Therefore it knows its whole self ' (Scit se igitur totam. Trin. 10.4.6; cf. De Genesi ad Litteram 7.21.28). The Latin text of De Trinitate is that of Mountain (1968). Translations of Augustine are my own, but I have consulted Agaësse and Moingt (1955) and Matthews (2002). 16 Following Castañeda (1966;, I use ' * ' to indicate the self-conscious or irreducibly reflexive nature of the relevant cognisance or thought (cf. Lewis 1979). 17 Agaësse and Moingt (1955: 2.604-5) and Bermon (2001: 92) seem to take the argument to be largely rhetorical. Pepin (2000) suggests the argument is deficient but doesn't make clear how. 18 As an anonymous reader has suggested, Augustine's view may draw further support from the fact that the mind knows itself * as knowing something, i.e. qua knower and qua entity that is wholly involved in the relevant activity (see also below).
Thus, Augustine is happy to say 'the whole mind, then, is present to itself ' (tota ergo sibi praesto est, Trin. 10.4.6) and that, in knowing itself, there is no part of the mind which the mind does not know. What this knowledge or acquaintance amounts to is not made entirely clear but Augustine emphasises that being acquainted with or knowing the whole of the mind does not imply omniscience about the mind (cf. non dico totum scit, Trin. 10.4.6). 20 Instead, Augustine's point is that-in the mind's knowing itself-there isn't some hidden part of the mind with which it is not acquainted, i.e. if x knows the whole of α, then there exists no y such that y is a part of α and x is not acquainted with y. Analogously, one might know New York by being acquainted with every part of it (including, e.g., Staten Island), without thereby being omniscient about New York.
Thirdly, Augustine does not merely make the case that the mind is acquainted with the whole of the mind, but that it has knowledge of its activities and has self-conscious, first-person, or de se cognisance of itself * as a mind performing these activities (Trin. 10.3.5-6). While Napoleon might know that Napoleon wrote a novella without knowing that he * is Napoleon or that he * wrote a novella, Augustine maintains that when the mind inquires into the mind it is aware that it * is seeking itself and that it * is a mind (cum quaerit mens quid sit mens, novit quod se quaerat profecto novit quod ipsa sit mens, Trin. 10.4.6). These activities seem to be introspectively luminous and thus, especially when inquiring into itself, the mind's acquaintance with itself is typically accompanied by certain propositional knowledge about itself performing the relevant activities. Thus, for instance, the mind knows that it itself * is knowing something (se aliquid scientem scit, Trin. 10.3.5), knows that it itself * is seeking something (quaerentem se iam novit. . . Novit enim se quaerentem, Trin. 10.3.5), knows that it itself * lives (novit autem vivere se, Trin. 10.4.6), and knows that it itself * is a mind (mentem se esse iam novit, Trin. 10.4.6, 10.14).
Fourthly, the mind's self-knowledge of some of these facts-most saliently, its knowledge that it * is a mind that knows, inquires, thinks, lives, etc.-is especially epistemically secure and immune to rational doubt (cf. Trin. 10.10.13-14; 15.12.21). The mind may not, for instance, mistake someone else's thinking for its own or vice versa (cf. Trin. 10.2.4-3.5) and, as Augustine emphasises on several occasions, it is impossible to rationally doubt first-person propositions such as <I am alive> and <I think> because entertaining such thoughts guarantees their truth (Trin. 10.10.14; 15.12.21; cf. De Civitate Dei 11.26).
Thus, on Augustine's view, the mind is immediately and directly acquainted with the whole of itself and enjoys epistemically secure knowledge of certain facts about itself, such as that it is a mind engaging in certain intellectual activities (e.g. inquiring, seeking, etc.). However, even if one grants all this, one might worry that such claims fall short of establishing that the mind knows its own essence (as the argument which Augustine goes on to develop, for which see Section III, seemingly requires). Thus, for instance, one might-in the manner of later medieval philosophers like Thomas Aquinas and Peter John Olivi-think that we should sharply distinguish the mind's cognisance of its activities (e.g. knowing, thinking, etc.) from its cognisance of its essence and that while Augustine might establish that the mind has cognisance of (at least some of) its activities, this falls far short of establishing that the mind knows its essence. 21 This is a fair worry, but a satisfying response is-I think-available once we appreciate that Augustine, like several Neoplatonists, seems to hold a dynamic or active conception of the mind's essence. 22 Thus, Augustine holds that in knowing its relevant activities (e.g. thinking, etc.) the mind knows its essence for its essence simply is these activities. This requires some explanation. According to what I am calling a 'dynamic' or 'active' conception of α's essence, α's essence is not constituted by certain dispositional properties which α must have in order to be what it is and which might or might not be manifest or active. Instead, α's essence is constituted by certain properties which it must have in order to be what it is and which are always manifest or active. On this conception, a glass's capacity to break (if we assume that such a capacity manifests itself only in the act of breaking) will not be part of its essence. In contrast, a fire's capacity to heat might be. Generally, if α is not necessarily manifestly F, then F is not part of α's essence.
32 For example, 'certainly, since the time it began to be, it has never desisted from remembering itself, understanding itself, loving itself ' (cum profecto ex quo esse coepit, numquam sui meminisse, numquam se intellegere, numquam se amare destiterit, Trin. 14.10.13). Cf. Brittain (2012b). 33  34 Note that although the mind is essentially active and always manifests some intellectual activity, many of its intellectual activities or capacities are not always manifest and there need not In sum, Augustine thinks the mind's essence is constituted by certain intellectual properties or activities which it always manifests. The mind is acquainted with these activities and, in being so acquainted, thereby grasps its essence. Granting the relevant assumptions about 'active' essences (which were not uncommon in later antiquity), it seems that Augustine thus has some reason to think that the mind grasps its essence. However, one might worry that this is still too quick because even if the mind's essence is constituted by certain activities it always manifests, it doesn't follow that every activity the mind always manifests is thereby part of the mind's essence or that in being aware of these activities the mind knows that they constitute the mind's essence.
I think the best response to this worry lies in appreciating that the cognisance of the mind's essence Augustine requires for the sake of his argument is actually relatively modest. As we shall see below, an important part of Augustine's case for the incorporeality of the mind does not centrally rely upon the claim that the mind knows its essence (see Section IV) while another part of Augustine's case for the incorporeality of the mind does not require knowing the mind's essence in such a way that one articulately knows what its essence is (i.e. does not require that x knows α's essence in such a way that if F is an essential property of α, then x knows that F is an essential property of α) or that one is consciously aware of the relevant knowledge (see Section III). Instead, all that the relevant part of Augustine's argument requires is that the mind grasps its essence in such a way that if F is an essential property of α, then x is able to tell that α is F (the argument does not require being able to tell which of these Fs is part of the mind's essence). This more modest grasp of a thing's essence, which we might call knowing a thing comprehendingly (cf. Lowe 2008), does seem to be plausibly supported by the considerations Augustine offers.

III. ESSENCE, DOUBT, AND INCORPOREALITY
Given Augustine's claims about the mind knowing itself, it might seem puzzling that there should be so much disagreement and widespread error about the nature of the mind (cf. Trin. 10.5.7). However, Augustine thinks that many minds-most notably those of corporealists-often do not consciously think of themselves (se cogitare) 35 and mix in false beliefs with their knowledge in such a way that they cannot adequately distinguish what they know from what they merely suppose. As a result, they are prone to act as if they did not know themselves (Trin. 10.5.7; 14.5.8).
be (e.g.) any one particular item of knowledge which is always actualised (cf. Trin. 10.5.7) or any one particular thought which the mind is always consciously thinking. 35  Augustine offers a diagnosis, which has both Platonic ancestry and Cartesian descendents, 36 according to which corporealists rely excessively upon the bodily senses and, as a result, become glued or conjoined to bodily things (Trin. 10.5.7-7.9, 8.11). They are inclined to think that the mind is corporeal and can be pictured by means of quasi-pictorial representations (imagines, phantasiae, Trin. 10.7.10). Hence, a corporealist's mind 'is not able to be in itself without representations of bodies' (non valet sine imaginibus eorum esse in semetipsa, Trin. 10.8.11) and 'is not able to separate representations of sensible things from itself so as to make out the mind on its own' (rerum sensarum imagines secernere a se non potest, ut se solam videat, Trin. 10.8.11). As a result of this dependence upon seemingly quasi-pictorial representations-without which corporealists are unable to think of the mind (or anything else, In [A], Augustine echoes his earlier remarks about corporealists going wrong in attributing to the mind properties which it does not possess. For instance, the mind of a corporealist might know that it * understands, but merely thinks that it * is air and that air understands [B]. Thus, when attempting to think of itself as a thing which understands, the corporealist's mind ends up thinking that a corporeal thing understands. To avoid this error, the corporealist needs 36  , Augustine offers some guidance as to how this may be put into practice. By appealing to the seemingly intractable disagreements amongst corporealists about what the mind is made of (cf. De Civitate Dei 8.2, 5), 38 and contrasting such conflicting beliefs with the rational certainty with which every mind knows that it * lives, thinks, and judges (Trin. 10.10.14-15; cf. Cicero Tusculan Disputations 1.29.70ff), Augustine argues that while it is known that the mind thinks (etc.), it is not known that the mind is made of fire (air, etc.). Thus far, Augustine has not attempted to directly establish that the mind is incorporeal. Instead, he has focused on distinguishing what the mind knows for certain from what it merely takes itself to know and has argued that-even by the corporealists' own lights-the mind does not know that it is constituted of some particular corporeal stuff. This argument, which we may call the Doubt Argument, seems to take the following form: (i) if x has reason to doubt that p, then x does not know that p; (ii) for any corporeal stuff F, the mind has reason to doubt that the mind is F; (iii) for any corporeal stuff F, the mind does not know that the mind is F.
In support of (i), Augustine appeals to the view that knowing that p requires a firm grasp of reasons for thinking that p and is inconsistent with there being intractable disagreement over whether p. 39 In support of (ii), Augustine exploits the seemingly rationally irresolvable disagreements among corporealists concerning what corporeal stuff the mind is constituted by (cf. Cicero Tusculan Disputations 1.11.23; Nemesius De Natura Hominis 2). These seemingly intractable disagreements act as defeaters for the relevant parties and Augustine thus argues that corporealists should admit that they themselves have reason to doubt (and thus do not know) that the mind is constituted of some particular corporeal stuff (e.g. fire, etc).
In what follows, Augustine aims to move from the fact that the mind has a comprehending cognisance of itself (i.e. has the relevant grasp of its essence) 38 Cf. Aristotle De Anima 403b31ff; Cicero Tusculan Disputations 1.9.18ff; Nemesius De Natura Hominis 2.
39 Contra Academicos 1. 3.7, 7.19; 2.5.11, 6.14; 3.3.5, 9.18, 9.21; Enchiridion 7.20; Soliloquia 1.3.8-4.9; De Quantitate Animae 30.58; De Libero Arbitrio 2.3.8-9; De Utilitate Credendi 11.25; Retractationes 1.14.3. Cf. 'whenever two people arrive at contrary judgements about the same thing, it is certain that at least one of the two is in error and it seems that neither has knowledge' (Descartes Regulae AT 10:363). and that the mind has reason to doubt that it is corporeal (and thereby does not know that it is corporeal) to the claim that the mind is not corporeal: All these people do not attend to the fact that the mind knows itself even when it seeks itself, just as we have already shown. But in no way can something rightly said to be known while its essence is unknown (Nullo modo autem recte dicitur sciri aliqua res, dum eius ignoratur substantia). Accordingly, when the mind knows itself, it knows its essence and since it is certain about itself it is certain about its essence. Moreover, it is certain about itself, as is shown by what has been said previously. But it is not at all certain whether it is air, or fire, or some [other] body, or anything corporeal (Nec omnino certa est, utrum aer, an ignis sit, an aliquod corpus, vel aliquid corporis). Therefore, it is none of these things (Non est igitur aliquid eorum). (Trin. 10.10.16) Call this the Essence Argument. The argument-which has certain superficial similarities with Descartes' argument for a real distinctness between mind and body (Meditations AT 7:78)-is compressed, but it is clear that Augustine aims to remind readers that the mind knows its own essence, and that since it does not know that it is any particular corporeal stuff, it is not corporeal. This last step might seem obscure, but it seems that-if we take into account Augustine's prior discussion (Trin. 10.10.13-14, discussed above)-the argument is best understood as follows: 40 (1) if x knows α comprehendingly, then x knows α's essence; (2) the mind knows itself comprehendingly; (3) the mind knows the mind's essence; [from 1, 2] (4) if x has reason to doubt that p, then x does not know that p; (5) for any corporeal stuff F (e.g. fire, air, etc.), the mind has reason to doubt that the mind is F; (6) for any corporeal stuff F (e.g. fire, air, etc.), the mind does not know that the mind is F; [from 4, 5] (7) if x knows α's essence and F is an essential feature of α, then x knows that α is F; (8) for any corporeal stuff F (e.g. fire, air, etc.), being F is not an essential feature of the mind; [from 3, 6, 7] (9) for any α, if being some corporeal stuff F (e.g. fire, air, etc.) is not an essential feature of α, then being corporeal is not an essential feature of α; (10) being corporeal is not an essential feature of the mind. [from 8, 9] 40 My construal may be contrasted with that of Matthews (1992: 40-1), who understands this argumentative stretch as follows: (1) If x knows y, then x knows the substance of y.(2) If x knows the substance of y, then for any stuff z, if y is z, then x is certain whether y is z. (3) The mind knows itself.(4) The mind knows its substance.(5) For any stuff z, if the mind is z, then the mind is certain whether it is z.(6) The mind is not certain whether it is air (or fire, or a body). (7) The mind is not air (or fire, or a body). This construal has been closely followed by several subsequent treatments (e.g. Brittain 2012a; Matthews 2000; Niederbacher 2014).
Thus, from the fact that the mind knows itself comprehendingly, it follows that the mind knows its essence ((1)-(3), see Section II). Augustine then appeals to his earlier Doubt Argument to argue that the mind does not know it is made of any corporeal stuff F because for any corporeal stuff F, the mind has reason to doubt that it is constituted by F ((4)-(6)). As per (7), Augustine's argument does not require that the mind knows its essence in such a way that it is able to articulate its essence or what its essential properties are but merely that if F is an essential property of the mind, then x is able to tell that the mind is F (see Section II). Given the dynamic or active conception of essence Augustine shares with some later Platonists (according to which a thing's essential properties are always manifest), such a claim has, I suggested, some warrant. Since the mind does not know that it is made of any corporeal stuff F, it follows that being a particular corporeal stuff F is not an essential feature of the mind (i.e. (8)). Furthermore, since it is not the case that being made of any particular corporeal stuff F is an essential feature of a thing, then being corporeal is not an essential property of that thing (i.e. (9)) and it follows that the mind is not essentially corporeal (i.e. (10)).
As regards (1)- (3) and (7), granting Augustine's views about the mind's dynamic or active essence offers plausible grounds for thinking that the mind has a grasp of its essence which suffices for the needs of this argument while also not being excessively demanding. The Essence Argument is thus not vulnerable to one of the principal objections which have been raised against it (i.e. that Augustine has no grounds for claiming that the mind knows its essence, see footnote 7). However, this is not to say that the argument is sound or even dialectically successful. In fact, it faces at least three significant objections which have not been adequately appreciated. These are best discussed in turn.
First, as I have construed it, Augustine's argument seems to fall short of its desired conclusion because it does not establish that the mind is incorporeal, but merely that the mind is not essentially corporeal (contrast other accounts of the argument, e.g. that of Matthews cited in footnote 40 above). While this is indeed a gap in Augustine's argument (and one which has been overlooked by most existing treatments), it seems that Augustine can in fact readily establish his desired conclusion so long as he thinks that being corporeal or incorporeal is not merely one property among others, but is part of a thing's essential features in such a way that if a thing is (in)corporeal, then it is essentially (in)corporeal. That is to say, Augustine's argument is best construed as continuing thus: (11) for any x, ((if x is corporeal, then x is essentially corporeal) and (if x is incorporeal, then x is essentially incorporeal)); (12) being corporeal is not a property of the mind; [from 10, 11] (13) for any x, x is either corporeal or incorporeal; (14) the mind is incorporeal. [from 12, 13] (15) the mind is essentially incorporeal. [from 11, 14] Given (11) (a claim which Augustine comes close to articulating elsewhere and which has some independent plausibility), 41 Augustine's argument establishes not only that being corporeal is not an essential feature of the mind (see (10) above), but also that the mind is not corporeal at all (i.e. (12)). This is Augustine's explicitly stated conclusion in Trin. 10.10.16. Moreover, given the plausible disjunction that anything is either corporeal or incorporeal (i.e. (13)), Augustine is equally entitled to draw a stronger conclusion: that the mind is incorporeal (14), and in fact even that it is essentially incorporeal (15). Accordingly, whether we take (12), (14), or (15) as Augustine's desired conclusion, it seems that Augustine can validly establish it.
The second and third worries are less easily dealt with. The second worry is that, due to the use of the Doubt Argument, Augustine's Essence Argument seems vulnerable to reductio. Simply put, by parity of reasoning, a corporealist could argue that there is (seemingly) intractable disagreement over whether the mind is incorporeal or not (cf. Nemesius De Natura Hominis 2), that the mind thereby has reason to doubt that it is incorporeal, and that the mind thereby does not know that it is incorporeal (cf. (6) above). Given that the mind knows its essence, it follows that being incorporeal is not an essential feature of the mind and that Augustine's argument does no more to establish the mind's incorporeality than its corporeality.
The third worry concerns (4)- (6) and (9) and turns upon the fact that ¬K x ∃F[the mind is F] does not follow from ∀F¬K x [the mind is F]. That is to say, just because, for any corporeal stuff F (e.g. fire, air, etc.), x does not know that the mind is F (e.g. fire, air, etc.), it doesn't thereby follow that x does not know that the mind is constituted by some corporeal stuff or other. Analogously, it might be the case that for any particular lottery ticket, one has reason to doubt or does not know that that particular ticket will win. However, it does not thereby follow that one has reason to doubt or does not know that some lottery ticket or other will win. Equally, just because being made of some particular corporeal stuff (e.g. fire) is not part of the mind's essence, one might worry that it doesn't follow that being corporeal (i.e. being made of fire or air or whatever) is not part of the mind's essence. Accordingly, even though the corporealists disagree about whether the mind is fire or air (or whatever), and thereby-we shall grant-have reason to doubt that it is fire (air, etc.), it doesn't follow that the corporealists thereby have reason to doubt that it is fire or air (or whatever). 42 41 Cf. 'the soul is not corporeal; however, it is necessary that anything made out of the corporeal elements is corporeal' (anima non sit corporea, quidquid autem ex mundi corporeis elementis fit, corporeum sit necesse est, De Genesi ad Litteram 7.12.19). Augustine's account of the resurrection of the body  also seems to support (11) and it is worth emphasising that (11) is significantly weaker than the claims made by various recent essentialists (e.g. Forbes 1980;Kripke 1980: 113ff;Putnam 1975). 42 Moreover, the corporealists did in fact agree on certain relevant features. Thus, for instance, the Stoics and Epicureans agreed that the soul must be a subtle (λεπτoμερής) body (e.g. Epicurus

IV. REPRESENTATION, COGNITION, AND INCORPOREALITY
We have thus far seen that Augustine's Essence Argument is somewhat different than has often been thought and its principal flaw is not so much that Augustine offers no grounds for thinking that the mind grasps its essence, but that even if one grants this claim there are still several significant further objections. The first of these, I have argued, does admit of a plausible response on Augustine's part, but the second and third reveal more significant flaws in Augustine's Essence Argument. In order to appropriately respond to these objections and press his case for the incorporeality of the mind, it seems that Augustine should reject the claim that the disagreement over whether the mind is incorporeal or corporeal is rationally intractable and that he should not merely provide reason to doubt that the mind is fire or that the mind is air but either provide reasons to doubt that the mind is anything corporeal whatsoever or else provide reasons for thinking that the mind is incorporeal (e.g. by arguing that that the mind has certain features whose presence suffices to indicate that it is incorporeal, cf. Descartes Meditations AT 7:78-9, 85-6; 9:215). 43 Immediately following the Essence Argument, Augustine offers further argument for the incorporeality of the mind to such an effect: [A] The mind thus thinks of fire or air in the same manner as it thinks of any other bodily thing (Sic enim cogitat ignem aut aerem, et quidquid aliud corporis cogitat). But it is in no way possible that it should think of that which it itself is in the same way as it thinks of that which it is not (Neque ullo modo fieri posset ut ita cogitaret id quod ipsa est, quemadmodum cogitat, id quod ipsa non est). It thinks of all these things -whether fire, or air, or this or that body, or some part thereof, or a corporeal structure or combination by means of an imagined appearance (phantasia imaginaria). And it is not said to be all these things, but one of them. However, if it were one of them, then it would think of that one differently than the others (Si quid autem horum esset, aliter id quam cetera cogitaret), [B] not by some imaginary representation -as it thinks of absent things (either those very things or things of the same kind) which have been touched by the bodily senses, but by a certain kind of inner presence that isn't simulated, namely a real presence. For there is nothing more present to it [the mind] than itself. (Trin. 10.10.16) Call this the Representation Argument. Whereas Augustine's earlier arguments exploited disagreements among the corporealists to undercut their grounds for thinking that the mind was corporeal (Trin. 10.10.14), Augustine here aims to directly rebut the corporealists' views and offers reason to think that the mind is not made of air of fire or any corporeal stuff whatsoever. As I Epistula ad Herodotum 63-4; Galen Definitiones Medicae 19.355 K = SVF 2.780; Hierocles 4.38-53 = LS 53B; Nawar 2020b). 43 Descartes seemingly argues that thought is not a mode of extension or extended substance, that thinking things lack extension, and that minds are indivisible but extended things are divisible (AT 3:475-6;4:120;7:78-9, 121, 227, 355;cf. Rozemond 1998). understand it, the kernel of the argument is offered in [A] and has the following form: 44 (I) for any corporeal stuff F (e.g. fire, air, etc.), the mind cognises F but does not cognise F in a distinctive way; (II) if x is F, then (if x thinks of F, then x cognises F in a distinctive way); (III) for any corporeal stuff F, the mind is not F.
In [B], Augustine goes on to expand upon the manner in which the mind's cognisance of itself is distinct from its cognisance of ordinary corporeal things and there are several important points to appreciate about Augustine's argument.
First, (I) seems plausible or at least dialectically effective and defensible. For any relevant corporeal stuffs (e.g. fire, air, etc.)-and their composites-one cares to consider, it seems that the typical mind does not think of or represent those corporeal stuffs in a significantly distinctive way. That is to say, with significantly greater or lesser reliance upon imagination or in such a way that it is able to cognise it either better (e.g. more easily, more fully) or worse (e.g. with more difficulty, less completely) than it does other relevant corporeal stuffs.
Secondly, while Augustine may speak of a particular kind of thought occurring through presence and he-like many other ancients and medievals-often finds it attractive to explain cognisance and representation by positing some kind of isomorphism or similarity between a representation and what it represents (e.g. Omnis imago similis est ei cuius imago est, De Genesi ad Litteram imperfectus liber 16.57-8), 45 (II) is in fact a weaker and more dialectically effective claim. It does not require taking representations to represent through isomorphism and should prove acceptable to most interlocutors in the relevant ancient debates 44 Detailed discussions of this argument are brief. Matthews offers the following gloss (2005: 51): (1) if the mind were made of some kind of physical stuff, then the mind, simply by being fully present to itself, would think of the physical stuff it is made of.(2) The mind, simply by being fully present to itself, does not think of any physical stuff.Therefore, (3) The mind is not made of any kind of physical stuff.Brittain offers the following (2012a: 132): (1) The mind is entirely present to itself.(2) It is not present to itself as something material.(3) So the mind is not material.These readings, which focus primarily on Augustine's remarks in [B], turn upon more controversial claims and attribute a less convincing argument to Augustine. Thus, on Matthews' reading (2005: 51) over representation and whether cognition occurs by like of like (so that x representing F-ness requires or is facilitated by x being or becoming F; cf. Sextus Empiricus Adversus Mathematicos 1.303) or by like of unlike (so that x being F precludes or hinders x from representing F-ness; cf. Theophrastus De Sensibus 1-2, 25ff). 46 Augustine's argument is dialectically effective in that whether x's representing F stands in some special relation to (e.g. requires, is facilitated by, is impeded by) x's being F (as is held by those who hold that like is known by like) or to x's not being F (as is held by those who hold that like is not known by like), (II) should prove acceptable to Augustine's dialectical opponents.
Thirdly, just as with the second objection faced by the Essence Argument, a corporealist might attempt to resist Augustine's Representation Argument by arguing that neither does the mind think of itself nor of incorporeal items in a distinctive way. However, Augustine has a ready response. In [B] Augustine reminds the reader that-in contrast to its cognisance of corporeal thingsin cognising itself the mind does not require quasi-pictorial representations, testimony, or defeasible inference but is instead always immediately present to itself (cf. Trin. 9.3.3; 10.7.9, 9.12). Equally, while the cognisance of corporeal things we attain through our senses is always vulnerable to a significant degree of sceptical doubt (cf. Contra Academicos 3.6.13, 11.26; De Diversis Quaestionibus Octoginta Tribus 9), the inner knowledge (intima scientia) we have of our minds is extremely rationally secure (Trin. 15.12.21; cf. Trin. 10.10.13-14) in a manner which finds parallel only in the mind's cognisance of certain incorporeal objects such as numbers (cf. De Anima et eius Origine 4.19.30-20.31). 47 Fourthly, rejecting the claim that the mind knows its essence is not fatal to The Representation Argument. That is to say, the claim that the mind knows its essence plays a supporting role in establishing that the mind knows itself in a distinctive way and thereby ensures that The Representation Argument is not vulnerable to the kinds of objections faced by Augustine's prior arguments. However, The Representation Argument does not require accepting that the mind knows its essence. It merely requires the (much weaker) claim that the mind's cognisance of itself is distinctive in the relevant way.
While it lies open to the corporealist to offer an alternative account of cognition or representation (such that (II) is rejected) or else to press the case that the mind's cognisance of itself is not distinctive in the relevant way(s), such responses incur a significant price. Rejecting (II) requires that the corporealists significantly revise their accounts of representation and cognition (in a manner for which there was arguably little precedent in antiquity). Equally, insisting that one's cognisance of one's own mind is on a par with one's cognisance of ordinary corporeal things seems to entail that the corporealist should abandon any pretensions to epistemically privileged self-knowledge (which were dear to at least some of Augustine's corporealist opponents, such as Vincentius Victor, cf. De Anima et eius Origine 4.2.2ff). Either way, it seems that Augustine's argument has some claim to being dialectically effective against its principal corporealist opponents and that rejecting Augustine's claims about the mind's incorporeality comes at a significant price and requires that his corporealist opponents rethink some of their central philosophical commitments.

V. CONCLUSION
In this paper, I have examined Augustine's case for the incorporeality of the mind in De Trinitate 10. I clarified the ways in which Augustine takes the mind's self-knowledge to be distinctive and epistemically privileged and argued that Augustine's claim that the mind has some grasp of its essence is not ungrounded, but is instead supported by a dynamic or active notion of essence and certain claims about the way the mind cognises itself (Section II). I then examined how Augustine attempts to establish the mind's incorporeality by means of his Essence Argument. This argument is interesting but faces several significant objections which have hitherto not been adequately appreciated (Section III). Finally, I examined how Augustine appeals to The Representation Argument to establish the mind's incorporeality in a manner which addresses the objections faced by Augustine's earlier arguments with some dialectical efficacy (Section IV). I thus hope to have shown that Augustine's case for the incorporeality of the mind De Trinitate 10 is somewhat different and arguably somewhat more successful than has often been thought and to have thus shed some light on its nature, its interest, and its place in the history of philosophical thought about the mind. 48