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Review of Travis on Perception

posted 8 Jul 2015, 04:11 by Keith Wilson   [ updated 24 Feb 2017, 11:53 ]

Some time ago I reviewed Charles Travis’s Perception: Essays After Frege for Notre Dame Philosophical Reviews. I always meant to go back to it as (believe it or not!) I actually read the whole book and had comments on other essays that didn’t make it into the final text due to reasons of space. Thankfully, I’ve since had the opportunity to return to some of this material in preparing a chapter-length discussion of Travis’s argument from looks (see below) in ‘The Silence of The Senses’ — a topic I covered extensively in my PhD thesis — that will hopefully be appearing later this year in a volume edited by Tamara Dobler and John Collins entitled Charles Travis on Language, Thought, and Perception, published by OUP (watch this space!).

In the meantime, here is a slightly updated version of my review which includes a few additional notes and clarifications as a result of having revisited this material, as well as references to relevant forthcoming papers by Travis and Berit Brogaard in a special issue of Topoi that I am co-editing with Roberta Locatelli of the University of Warwick. The text is reproduced by kind permission of the editor of NDPR, and thanks to my former Sussex colleague, Lucy Allais, for helpful and illuminating comments on the debate with McDowell and Kant. As always, comments and feedback welcome.

Charles Travis, Perception: Essays After Frege

Oxford, 2013, 420pp., $99 (£50), ISBN 978-0-19-967654-5

Reviewed by Keith A. Wilson, University of Glasgow

Charles Travis’s latest collection on perception brings together eleven of his previously published essays on this topic, some of which are substantially revised, plus one new one. The intentionally ambiguous subtitle hints at the author’s endorsement of Fregean anti-psychologism, though influences from Wittgenstein and Austin are equally apparent. The work centres around two major questions in the philosophy of mind and perception. First, Travis argues against the view that perceptual experience, as distinct from perceptual judgement or belief, is representational, and so belongs to what Travis calls “the conceptual”. This is contrasted with the “non-conceptual”, or “historical”; that is, environmental particulars which lack the generality of representational thought.1 The second is what Travis calls “the fundamental question of perception”; namely, how can perceptual experience make the world bear (rationally) upon what we are to think and do? The answer, he argues, cannot be found in terms of relations between thoughts — a purely conceptual affair — but in the way that thought is itself grounded in the particularly of experience. For perceptual experience to bear rationally upon thought at all — or, in more familiar Fregean terms, to bring ‘objects’ under ‘concepts’ — perception must first make environmental particulars available to cognition. Thus, Travis argues, experience cannot itself be ‘conceptual’, or representational, on pain of undermining the very thing that grants us a recognisable, and so thinkable, world at all.

The twelve essays, presented in order of their composition and spanning almost a decade, develop these central themes in different and sometimes surprising ways. In Essay 2, for example, we learn that Frege is not only the father of modern logic, but of disjunctivism, and that claims concerning sense data are, according to Frege’s notion of thought, not truth-evaluable. Whilst Travis’s prose can be dense and heavy-going at times, it is rarely entirely obscure or impenetrable, and, as such, rewards patient study. Since each essay is intended to be self-contained, there is an inevitable element of repetition, particularly of the central Fregean claims (set out most explicitly in Essay 9), though this is generally more helpful than redundant. The overall impression is that of a thinker approaching his subject matter from a variety of directions in order to construct a more detailed and comprehensive map of the territory — albeit one that may seem somewhat unfamiliar to those more accustomed with the prevailing representationalist orthodoxy.

The essays also help to situate Travis’s thought in relation to other philosophers in the field including, though not limited to, McDowell (Essays 1, 4, 6 and 8), Peacocke (Essays 1 and 5), Evans (Essays 5 and 10), Wittgenstein (Essay 3 and throughout), Ayer (Essay 3 and 7), Putnam (Essay 6), Anscombe (Essay 7), Kant (Essay 8), Burge (Essay 9), Fodor (Essay 10), H. A. Prichard and Thompson Clarke (Essay 11), and Moore (Essay 12). Due to considerations of space, I will restrict myself to commenting on just a few of these, though the following themes are characteristic of the whole.

The Silence of the Senses

Essay 1 is a revised version of Travis’s ’The Silence of the Senses’ (2004), and targets the view that visual experiences have representational content — something that Travis argues involves a kind of category mistake. To perform the role that representationalists assign to such content in the formation and justification of judgements and beliefs — in the simplest case, endorsing it ‘at face value’ — perceptual experiences must, Travis argues, have personal-level content that is “recognizable” to the subject — a claim that Burge (2010) strenuously denies. While the relevant notion of recognizability is never fully explained, a subsequent essay suggests the minimal condition that the subject is able to grasp, though not necessarily elucidate, what it would take for that experience to be accurate or veridical. To qualify as representation-to the subject — “allorepresentation” in Travis’s terms — visual experiences must identify some particular way for the world to be; i.e. they must have objective truth or accuracy conditions. Travis’s argument from looks, as I will call it, then aims to show that such conditions cannot be discernible on the basis of perceptual appearances alone since (a) visual looks are comparative, and so do not identify any objective way for the world to be, and (b) epistemic, or ‘thinkable’, looks are not purely perceptual, and so cannot make the relevant content recognisable solely on the basis of what is visually available to the subject in experience. This presents the representationalist with the following dilemma: either (i) they must elucidate some further notion of looks that combines elements of both visual and thinkable looks — a task that Travis argues is impossible; or (ii) perceptual contents are not recognisable on the basis of visual appearances alone, in which case it remains to be specified precisely what are they recognisable on the basis of, if they are to play any substantive role in the perceiver’s conscious mental life.2

A possible response to the first horn of this dilemma is to claim that so-called ‘non-comparative’ or ‘phenomenal’ looks (Jackson 1977; Byrne 2009) are capable of making the relevant content recognisable. However, such content is arguably only capable of representing the phenomenal features of experience itself, and not the states of external objects, thus undermining its supposed justificatory role.3 Furthermore, this response is arguably rendered dialectically ineffective by the availability of purely comparative analyses of phenomenal looks (Martin 2010; Brewer 2013).4

A response to the second horn of Travis’s dilemma might attribute the relevant recognisability to the external individuation of higher-order states (cf. Burge 1988), or the action of conceptual capacities (McDowell 2008). However, standard accounts of privileged access do not translate well to the case of perceptual experience, which is not self-verifying in the manner of higher-order thought, and the relevant capacities might equally well be ascribed to judgement or belief as to experience per se, thus undermining the representationalist position.

Finally, one might choose to reject Travis’s requirement that experiential contents must be “recognizable” , à la Burge (2010). However, this places severe constraints upon the role that such content can play in the conscious life of the perceiver, negating much of the intuitive appeal of view according to which the subject can simply tell of any given perceptual experience what is represented therein. (Note that while it remains unclear why this issue could not be addressed by externalism about justification or cognitive availability of perceptual content in a way that is consistent with the central claims of representationalism, this would itself be an interesting consequence of Travis’s argument.)

The revised version of ‘Silence’ improves upon the original in several respects. The terminology has been updated to forestall the misunderstanding (cf. Byrne 2009; Siegel 2010) that it concerns the lack of any sense of the English ‘looks’ that captures the representational content of visual experience. Rather, Travis intends to engage with the metaphysics and justificatory role of visual appearances, qua looks, and not merely their semantics. In place of “looking like” and “looking as if”, we now find “visual looks” and “thinkable looks”, which correspond to Chisholm’s (1957) “comparative” and “epistemic” uses, respectively. Gone too are the references to “demonstrable looks” which formed a confusing and unnecessary feature of the original. The result provides a substantive and powerful, albeit perhaps not wholly decisive, objection to many standard representational views of perception that has yet to be adequately addressed by their proponents. It also highlights an important distinction between the question of what individuates perceptual content, which has received much attention in the recent literature, with the question of its availability to the subject, which has not. Moreover, any view that posits different responses to these two issues will need to explain how the resulting contents remain in step, since if they can come apart then this opens up the possibility that we can be mistaken about how things appear to us in virtue of mistaking the content of our visual experiences. This contradicts the commonly held view that visual appearances are the sort of thing to which the appearance–reality distinction does not apply, thus yielding a further objection to the representational view.

Unlocking the Outer World

Essay 8, ‘Unlocking the Outer World’, is the only entirely new piece in the volume. In it, Travis considers the related question of how the representational content of experience could (per impossibile) come to have a “general shape” — propositional or otherwise — that is suitable for judgement. According to McDowell (2008), simply assuming that experience delivers such content without explaining how it is structured by the operation of the same cognitive faculty that is employed in judgement would be to fall prey to “the Myth of the Given”. One way of avoiding the Myth, if it is such, endorses a particular reading of Kant’s slogan that “The same function which gives unity to the various ideas (Vorstellungen) in a judgement also gives unity to the mere synthesis of various ideas in an intuition (Anschauung)” (Kant 1781/1789: A79–80/B105–106). Whilst McDowell’s interpretation of this passage as involving a single faculty or capacity is controversial, it is sufficiently widespread to make it a useful target. Against this view, Travis presses the following two Fregean points.

Abstracting somewhat from the details of Travis’s argument, in order to move from the “inner” world of subjective sense impressions — themselves subjective ideas (Vorstellungen) in the mind of some particular perceiver — to the “outer” world of thought, the relevant Vorstellungen must be brought under a concept, i.e. a rule. But according to Frege’s anti-psychologism, thought (Sinn) requires objective import, and so some objective criterion that determines whether particulars fall under the corresponding concept. However, argues Travis, there can be no objective criterion for whether Vorstellungen, which are purely subjective, fall under such a concept, and so no such concept. The structuring or unification of perceptual content cannot therefore be a result of the application of concepts (in Frege’s sense), and so McDowell’s interpretation of Kant’s slogan is untenable. Call this Frege’s private language argument (FPLA).

The difficulty with FPLA is that it neglects two important features of Kant’s transcendental idealism. First, it is not obvious why we should think of Kantian categorial concepts, such as those of space, time and propositional unity, on the model of Fregean empirical concepts. Rather, these are, for Kant, a priori conditions for the possibility of experience. If they did not correspond to any objective features of the world whatsoever — something that is doubtful, even under Kant’s transcendental idealism (see below) — then neither would the resulting judgements. However, it does not follow from this that there can be no such concepts. Provided that the relevant criteria holds for all suitably equipped perceivers, why should such ‘concepts’ possess purely objective truth conditions? Just as Frege held that first-personal thoughts involve a mode of presentation that is uniquely available to the thinker (a point that Travis discusses at length in Essay 9), categorial concepts may yield modes of presentation — of space, time, sensations, etc. — in ways that are uniquely accessible to each individual perceiver. Unlike Frege’s case of Dr. Lauben, however, the existence of an intersubjective criterion of application — perhaps in virtue of our common evolutionary heritage — would be sufficient to make the resulting judgements possible. No doubt Travis would object to this on the basis that such judgements are incapable of revealing an objective mind-independent world, but this hardly seems an objection to Kant, who argues that transcendental idealism is compatible with empirical realism (Kant 1781/1789: A370).

Travis’s primary target here, however, is not Kant, but McDowell, who he sees as illicitly appealing to a common unifying function between thought and perception that not only does not, but could not, exist. Travis’s argument against McDowell on this point is twofold. First, McDowell, unlike Frege, misdiagnoses the problem. There is no need for a unifying function since no such unifying is required. Thoughts are not built up out of a series of component parts, such as concepts. Rather, these ‘parts’ are themselves decompositions of thoughts — Frege’s “context principle” — which admit of many such possible decompositions. McDowell’s solution to the Myth is therefore misguided. Second, no amount of unifying that takes place within the conceptual domain can explain how environmental particulars, i.e. perceptible objects, are brought under concepts. Rather, this is a matter of relating the non-conceptual, or “historical”, to the conceptual — something that must go beyond the domain of the conceptual alone. Travis goes on to argue that a capacity for judgement necessarily involves being able to tell whether some particular — e.g. the familiar Austinian pig snuffling under the oak — instances a concept; e.g. of something snuffling. A sensitivity to what would count as such an instance under the relevant circumstances, i.e. “occasion sensitivity” (cf. Travis 2008), is therefore of the essence of judgement. But McDowell’s view allows no room for such sensitivity, since the relevant content is already fixed by experience, which is conceptual (though, importantly for McDowell, not propositional, and so not in itself evaluable for truth or falsity — a point that Travis appears to overlook). Thus any subsequent endorsement of this content is no longer recognisably an act of judgement.

The effectiveness of these argument turns upon (i) precisely what we take the role of perception to be, and (ii) how much stock we place upon Travis’s notion of occasion sensitivity. On a ‘thin’ view of experience, perception merely makes environmental particulars available for cognition in thought and judgement, and so it seems we should reject McDowell’s conceptualism. On a ‘thick’ view of experience, however, perception also involves the detection of generalities, thereby diminishing the role of judgement. That the pig is snuffling, Travis and Frege agree, is not an object of perceptual awareness — it is a proposition, not a pig — and so any view according to which perception consists in the taking in of facts must be grounded in sensitivities to the relevant environmental particulars. One might worry that this debate threatens to descend into a purely terminological dispute over the meaning of the terms ‘experience’ (i.e. perception) and ‘judgement’ (i.e. cognition) with the two sides differing only on at which point they draw the distinction between the two, and so the point at which conceptual capacities may be said to come into play. Whilst this certainly captures part of what is at stake here, such a worry underestimates the structural differences between the two views, each of which assigns different roles to cognition and to the ‘reach’ of our rational capacities (Essay 4). The resulting exchange, which continues a long-running debate between Travis and McDowell,5 helps to sharpen our understanding of these issues, highlighting potential opportunities for further philosophical and empirical work in this area, for example in defining the nature of the relevant conceptual capacities.

Desperately Seeking ψ

Essay 9, ’Desperately Seeking ψ’, sees Travis turn his attention to Tyler Burge’s (2005) dismissal of disjunctivism on the grounds that it is “directly at odds with scientific knowledge” — a claim that, as Travis generously puts it, needs to be taken with a grain of salt. This essay is concerned as much with belief as with seeing, and argues that Burge’s view is incompatible with central Fregean doctrines concerning the essential publicity of thought.

Travis’s argument focuses upon Burge’s commitment to the existence of a ‘common factor’, or representational content — the eponymous ψ — between subjectively indistinguishable experiences of the following kinds:
  1. Perception; e.g. Sid, on esplanada, seeing Penelope Cruz (Travis’s example)
  2. Illusion; e.g. Sid having a perfect illusion as of seeing Penelope Cruz, but in which Penelope is replaced by a visually indistinguishable body-double
  3. Hallucination; e.g. Sid having an experience that is subjectively indistinguishable from one of seeing Penelope Cruz, but in which no seeing actually takes place.

On Burge’s view, each of the above cases will involve the representation of type-identical contents, despite the objects of Sid’s experience being quite different, or indeed there being no such object in case 3. Consequently, for Burge, such experiences will involve different token-contents — or perhaps no token content at all. Disjunctivism, as Travis defines it, consists in the denial that there is any such type-identical content, and so any common factor. This is incompatible with Burge’s “Proximality Principle”, which takes the total antecedent psychological state of the individual, along with proximal inputs to the relevant perceptual systems, i.e. ψ, to be “implicit in causal explanation of all reasonably well-developed empirical perceptual theories that I know of” (op. cit. 22). Assuming no deficit in Burge’s knowledge of these areas, the outcome is not a happy one for disjunctivism.

Travis’s strategy here is to drive a wedge between Burge’s psychological account of perceptual states and Frege’s logical one, claiming that Burge illicitly slides from the former to the latter. For ψ to be the content of some possible thought, it must be both singular, i.e. its truth requires the presence of the relevant historical individuals — in this case Penelope — and essentially public, as per FPLA. However, whether a thought is singular or general is, according to Travis, a function of its decomposition, and not a property of the thought itself. Moreover, since ψ is consistent with the presence or absence of various objects — cases 2 and 3, respectively — then it cannot entail conscious awareness of those objects. It is, as Travis puts it, a mere Vorstellung, or subjective idea, in the mind of some particular perceiver.

Travis’s argument here is complex and concerns a disagreement over the individuation of a particular kind of psychological state, which for disjunctivists will be externalist, versus what fixes its content which, for Burge, will be anti-individualist; e.g. concerning historical facts about the evolution of the human visual system. Considerations of space preclude detailed discussion, but that ψ is not itself sufficient for a thought or perception of Penelope, qua particular historical individual, does not rule out its being an ingredient in such a state — a possibility Travis also considers, but dismisses somewhat peremptorily. This of course raises the question of what else, other than the presence of the relevant object, would be required to yield such awareness. However, since Burge is not concerned with conscious awareness per se — indeed, he claims that it plays no essential role in perceptual representation — it is unclear why this should constitute a objection to his view, or indeed why Frege’s notion of thought is appropriate here (a point Travis himself makes, albeit in a different context).

The main problem with the essay, however, is one that runs throughout the book, concerning its avowedly Fregean underpinnings. Here, as elsewhere, Travis rests considerable weight upon what Frege ‘showed’ or ‘argued’, but without providing us with the benefit of the relevant arguments as he understands them. Apart from some brief quotations which state, though do not establish, the relevant claims, the reader is left to take it on trust that Frege’s arguments do indeed establish beyond doubt that thoughts, for example, must be independent of their individual bearers, or that the truth conditions for thought, and so perceptual representation, must be wholly objective (see above). Whilst Frege’s views in the philosophy of logic and language will be familiar to most readers, the effectiveness of his arguments to establish these positions may remain open to question — The Basic Laws of Arithmetic I, p. XIX, being a case in point. No doubt Travis intends for inconsistency with Fregean principles to constitute a form of reductio against his opponents, but it is unclear why we should go along with him in accepting Frege’s view of thought as the only game in town. Of course, any alternative view will face a similar explanatory burden, but one might equally take Burge to be engaging in the project of establishing a philosophically respectable notion of objective representation, and so of thought, that enables reference to environmental particulars in a way that is consistent with central Fregean insights, albeit inconsistent with Travis’s interpretation of them. Given this possibility, it would be helpful to know precisely what Travis takes the decisive Fregean arguments to be, and why we should think of them as applying in the case of perception, which is not, by Travis’s own lights, a form of thought at all. In a sense, this is itself the project of the book, but it is one in which some of the foundations appear to be missing.


The above noted flaw aside, the present collection makes a stimulating and highly original contribution to many debates in contemporary philosophy of perception. Travis’s rehabilitation of Fregean anti-psychologism is a welcome and timely development, and the inclusion of new and updated material makes it a worthwhile addition to the corpus. This is true not only for the philosophy of perception, in which disjunctivism is already considered a serious contender by many, but in the philosophy of mind and psychology more generally, where talk of ‘representation’ and ‘representational content’ has become very much the norm, often with little thought being given to its theoretical and conceptual underpinnings. Indeed, it is unclear what philosophical talk about the content of conscious perceptual episodes, namely experiences, has to do with the kind of sub-personal representation that forms a standard part of psychological and neuroscientific causal explanations of brain mechanisms.

Overall, this collection presents a coherent and impressive case against the prevailing consensus that perception is representational, and is perhaps best read as setting the agenda for an alternative, non-representational understanding of perceptual psychology, as well as of the metaphysics of mind and consciousness more generally. As such, philosophers of mind, language and perception will find much of interest here, both in terms of building upon and collecting together Travis’s previous work in this area, as well as opening up new lines of enquiry in the debates about perceptual content, representation and disjunctivism.


Brewer, Bill (2008). ‘How to Account for Illusion’. In Disjunctivism: Perception, Action, Knowledge, A. Haddock & F. Macpherson (eds.). Oxford: Oxford University Press, pp. 168–80.

Brogaard, Berit (forthcoming a). ‘Perception Without Representation? On Travis’s Argument Against the Representational View of Perception’. Forthcoming in Topoi: An International Review of Philosophy.

Burge, Tyler (1988). ‘Individualism and Self-Knowledge’. Proceedings of the Aristotelian Society, 85 (11), pp. 649–63.

–––––– (2005). ‘Disjunctivism and Perceptual Psychology’. Philosophical Topics, 33 (1), pp. 1–78.

–––––– (2010). Origins of Objectivity. New York: Oxford University Press.

Byrne, Alex (2009). ‘Experience and Content’. Philosophical Quarterly, 59 (236), pp. 429–51.

Chisholm, Roderick M. (1957). Perceiving: A Philosophical Study. Ithaca, NY: Cornell University Press.

Glüer, Kathrin (2009). ‘In Defence of a Doxastic Account of Experience’. Mind and Language, 24 (3), pp. 297–327.

Jackson, Frank (1977). Perception: A Representative Theory. Cambridge: Cambridge University Press.

Kant, Immanuel (1781/1789). Kritik der reinen Vernunft. Frankfurt am Main: Insel, 1956.

Martin, M. G. F. (2010). ‘What’s in a Look?’. In Perceiving the World, B. Nanay (ed.). Oxford: Oxford University Press, pp. 160–225.

McDowell, John (2008). ‘Avoiding the Myth of the Given’. In John McDowell: Experience, Norm, and Nature, J. Lindgaard (ed.). Oxford: Wiley-Blackwell, pp. 1–14.

Raleigh, Thomas Bainbridge (2013). ‘Phenomenology without Representation’. European Journal of Philosophy. DOI: 10.1111/ejop.12047.

Travis, Charles (2004). ‘The Silence of the Senses’. Mind, 113 (449), pp. 59–94.

–––––– (2008). Occasion-Sensitivity: Selected Essays. Oxford University Press USA.

–––––– (forthcoming). ‘Deliverances’, Topoi: An International Review of Philosophy.

Wilson, Keith A. (forthcoming). ‘Are the Senses Silent: Travis’s Argument from Looks’. In Charles Travis on Language, Thought, and Perception, T. Dobler and J. Collins (eds.), Oxford: Oxford University Press.


1 Somewhat confusingly, non-conceptual representation also counts as ‘conceptual’ for Travis, as emerges in his discussion of Evans and Peacocke in Essay 5.

2 Cf. Wilson (forthcoming); for alternative formulations of Travis’s argument, see Brogaard (forthcoming) and Raleigh (2013).

3 Cf. Glüer (2009), and pace certain forms of reliabilism.

4 For the outline of such an argument, see Wilson (forthcoming).

5 A debate that is further continued in Travis (forthcoming).

Philosophy, Science Fiction and The Matrix

posted 3 Jul 2015, 07:04 by Keith Wilson   [ updated 7 Jul 2015, 06:12 ]

A couple of weeks ago as part of the Glasgow Science Festival, I had the opportunity to give a philosophical introduction of an outdoor screening of the sci-fi film The Matrix at the University of Glasgow (pictured above). Immediately beforehand, I also gave this impromptu interview in which I talk more generally about philosophy, science fiction and The Matrix.

Unfortunately, due to some technical problems on the night — or was it a glitch in the Matrix? — not all of the audience was able to hear my introduction, so I’ve included the (slightly edited) text of my introduction below. In it, I discuss the problem of external world scepticism and Robert Nozick’s ‘experience machine’ thought-experiment, both of which relate to central themes of the film. Comments welcome.

Introduction to The Matrix

I'd like to invite you to reflect on two philosophical questions that are raised by the film The Matrix. The first is: can we be sure that we're not in the Matrix?

Brains in Vats

The 18th century philosopher René Descartes considered a very similar question to this when he realised that he could doubt almost everything he thought he knew. Descartes reasoned that if he were dreaming, or being deceived by a malicious demon, everything would appear to him exactly the way it normally did, and yet the world might be completely different to the way that things seemed. In fact, the only thing Descartes found that he couldn't doubt was his own existence, because in order to do that he had to think, and if he was thinking, then he must exist. He made this realisation at the foundation of his philosophy, famously summed up by the phrase “cogito ergo sum”: I think therefore I exist. Other philosophers, however, have doubted even that.1

We know from our own experience that our senses — sight, hearing, smell, and so on — are unreliable, since we can be easily fooled by illusions, dreams, hallucinations, and the like. However, what if not just some, but all of your experiences were illusory? It seems at least plausible that such experiences could be created artificially by stimulating someone’s brain — with electrodes, for example. Those electrodes could be wired to a supercomputer which could be programmed to generate the exact patterns of electrical impulses that are normally produced by our sense organs and nervous system. It would seem to the unfortunate person whose brain was wired up in this way that she was experiencing everything normally, and yet all of her experiences would be nothing more than an illusion generated by the computer program, and not a reflection of the real world at all. Now imagine that the brain could be kept alive artificially outside of its body in a vat of nutrients, and you have what modern day philosophers like to call a ‘brain-in-a-vat’.

The Problem of Scepticism

This is just one example of a kind of scepticism—scepticism about the external world—but you can imagine others. Scepticism about other minds: perhaps everyone around you is not a thinking, living being like yourself, but a cleverly disguised robot that just looks like a human being. Scepticism about the past: perhaps the entire universe came into existence just five minutes ago, complete with traces and your memories of a past that never actually happened. Conspiracy theories work in much the same way, since any evidence you might have against the existence of the conspiracy might be misinformation created by the conspirators to throw you off the trail!

As Descartes realised, in each of these cases the problem is that any evidence you might take yourself to have that everything is as it appears to be is equally compatible with your being in the sceptical scenario. In the brain-in-a-vat case, for example, any experience that you can imagine to try and test whether or not you are a brain-in-a-vat could itself be an illusion generated by the computer program. Even worse, if the brain can't rule out the possibility that she’s really a brain-in-a-vat, and not in the real world, then you might wonder whether she can claim to know anything at all—except perhaps, like Descartes, that she exists.2 Note, however, that you could have evidence that you are a brain in a vat—something the filmmakers cleverly work into the plot of The Matrix.

At this point, you might be thinking that this kind of scenario seems sufficiently remote or unlikely that it’s of interest only to philosophers and sci-fi fans, and doesn’t threaten our knowledge of the world. But of course that’s exactly what the brain-in-a-vat would say, and yet all of her beliefs about the world are false! It seems only a matter of luck that we’re not in her predicament — if indeed that’s the case — and since we can't rule out being in a vat-world, you might then wonder whether we can claim to know anything at all. If that’s right, then it looks like we can’t be certain that we’re not brains-in-a-vat, or in the Matrix. Indeed, some scientists take seriously the possibility that the entire cosmos and everything in it, including us, could be part of a sophisticated computer simulation, and in the final part of the Matrix trilogy, the filmmakers hint that even the reality outside of the Matrix isn’t what it appears.

Nozick’s Experience Machine

The second question I want to invite you to consider is: given the choice, would you take the blue pill and live in the simulated world of the Matrix, or take the red pill and live in the real world?

Consider the following scenario. Imagine that, like some of the characters in the film, you’re given a choice of whether to live out the rest of your days in a simulated reality where you experience only good things and have a wonderful life. Alternatively, you could live your life in the real world with all of its flaws and imperfections, and no guarantee of happiness. Which would you choose? To make things easier, let's imagine that immediately after you made your choice, any traces of the decision would be wiped from your memory, so from that point on you would be completely unaware of whether you are living in a simulation or reality.

This scenario, or ‘thought experiment’, was posed by the philosopher Robert Nozick who argued that, while it might be fun to live in a simulated reality or ‘experience machine’ for a while, especially one that was programmed specifically to make you happy, given the choice most of us would prefer to take our chances in the real world. Why is that? Perhaps it demonstrates that we don’t care only about our own happiness, but it's important to us to live an authentic life in which we can genuinely engage with other people and make a difference to the world around us, even if it that means that we experience suffering. Or perhaps, without the ups and downs of life in the real world, we fear that happiness and pleasure would lose their meaning. In any case, it seems to matter to us whether or not we’re in the Matrix, even if we can’t be sure that we’re not.3

If you'd like to find out more about perception, illusions and the value of suffering, you can do so on the Centre for the Study of Perceptual Experience’s website, or come to one of our talks at the Glasgow Science Festival. In the meantime, sit back, relax, and enjoy the film… and if you have the strange feeling that all of this has happened before, then watch out, you might just be in the Matrix!


1 The Scottish philosopher, David Hume, for example, held that the self had no persisting substance, and consisted merely of a bundle of properties.

2 One potential solution that has been advanced to this problem is that concepts can only relate to the things that causes us to form them. The concepts of ‘brains’ and ‘vats’ therefore refer to the things that we experience in our current world. Now, if we were brains in vats, then our concepts would refer not to the grey squishy matter we had in our heads, but those electrical signals that are generated by the computer program that gave us the illusion of brains and vats in our simulated reality. Since we’re definitely not one of those, then it’s false by definition that we are brains in vats, even if we’re unlucky enough to inhabit a vat-world! Indeed, according to the Hilary Putnam, who advanced a version of this theory known by philosophers as semantic externalism, we lack the concepts to even express the question ‘Am I a brain in a vat’ in a way that it could possibly be true, since in the worst case our concepts would refer to the electrical impulses generated by the computer program, and not to brains or vats in the ‘real’ world, to which we have no access. However, his solution is hardly a reassuring one.

3 Note that absolute certainty might not be required for knowledge, in which case we might be able to know that we’re not in the Matrix despite being unable to prove it. However, even in this case it looks like we still can’t be certain about whether we have knowledge or mere belief, since we might merely think that we know and yet be mistaken.

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Engaging the Senses at the Glasgow Science Festival

posted 22 Jun 2015, 08:50 by Keith Wilson   [ updated 25 Jun 2015, 07:06 ]

A guest blog post I wrote for the AHRC Science in Culture Theme’s blog describing a series of events that I helped to organise as part of the Rethinking the Senses project and Centre for the Study of Perceptual Experience’s presence at this year’s Glasgow Science Festival.

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Taste and smell: the hidden senses

posted 6 Jan 2015, 20:12 by Keith Wilson   [ updated 6 Jan 2015, 20:13 ]

A blog post I wrote recently about the individuation of our sense(s) of smell for The Hidden Senses event, part of Being Human: A Festival of the Humanities.

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Job news

posted 24 Aug 2013, 10:07 by Keith Wilson   [ updated 25 Aug 2013, 03:28 ]

I’m happy to say that I will be returning to the University of Sussex next month as a fixed-term Lecturer in Philosophy, where I will be teaching undergraduate modules in the Philosophy of Mind and Perception, Philosophy of Science, and Plato, as well as an MA module on Mind and Reality. I really enjoyed the time I spent at Sussex earlier this year and look forward to rejoining the department, which also has several other new hires, on a full-time basis.

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Top tips for organising a PhD exchange visit

posted 10 Aug 2013, 09:28 by Keith Wilson   [ updated 10 Aug 2013, 11:15 ]

I just noticed that this article by Sarah Marten recently appeared on the website in which I talk about my experience as a visiting exchange student at the University of Columbia in New York. It also contains some tips for anyone who is thinking of organising such a visit—something I would highly recommend. Visiting and studying in New York was one of the highlights of my PhD experience, not to mention being where my wife and I got engaged!

The article is a companion to this piece, which describes my transition from a career in IT to one in philosophy. Comments on both, or other people’s exchange visit experiences, are welcome below.

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Call For Papers: Perception Without Representation [updated]

posted 22 Jul 2013, 01:52 by Keith Wilson   [ updated 28 Oct 2013, 15:59 ]

Topoi: An International Review of Philosophy
Special Issue – Perception Without Representation
Deadline for Submission: 15 September 15 November 2013

Topoi: An International Review of Philosophy, will publish a special issue on the topic of Perception without Representation. The final deadline for submitted papers is 15 November 2013.

Guest Editors:
Keith A. Wilson, University of Sussex
Roberta Locatelli, University Paris 1/University of Warwick

Invited Contributors:
Bill Brewer, King’s College, London
Berit Brogaard, University of Missouri, St. Louis
John Campbell, University of California, Berkeley
Jérôme Dokic, Institut Jean-Nicod, Paris
Naomi Eilan, University of Warwick
Matthew Soteriou, University of Warwick
M.G.F. Martin (TBC), UCL
Charles Travis (TBC), King’s College, London


According to current orthodoxy, common to philosophers, psychologists and cognitive scientists, perceptual states have representational content, i.e. they represent the world as being a certain way. The representational content of perceptual experience (which need not be conceptual) can be accurate or inaccurate, i.e. its representing that an object has certain properties can be veridical or not. An increasingly influential trend, however, has begun to criticise this view, instead claiming that perception has no content. On this view, to perceptually experience an object is not to represent it to be some particular way, but for the perceiving agent to stand in a particular relation to the object perceived—the so-called relational view.

Too often such debates have been dominated by mutual incomprehension, stigmatisation or mischaracterisation of the opponent’s position whilst failing to recognise its merits or even to take the alternative option seriously. This journal issue aims to clarify some different problems that are at stake within the current debate, highlighting various points of agreement and contention, and developing them in an original and constructive way.


The aim of the volume will be to set out the debate in a way that stimulates and encourages genuine engagement and progress on these important issues. We welcome contribution from both sides of the debate on (though not limited to) the following topics:
  • Is it true, as sometimes claimed, that the content view better explains perceptual phenomenology or phenomenal character?
  • What accounts of perceptual phenomenology are available to proponents of a relational view? Are these any more or less plausible than those of the content view?
  • Could perceptual appearances ever provide compelling evidence for or against the existence of representational content?
  • What is the explanatory role (or roles) of perceptual content in relation to phenomenal character, perceptual awareness and consciousness?
  • How does perceptual content (or the lack of it) bear upon the epistemic role of perception?
  • The relational view is sometimes taken to be the best, or most straightforward, way to make sense of the intuition that we have direct, unmediated access to objects and their properties. But in what sense does representational content constitute an intermediary? Conversely, how are we to make sense of such direct access in a content view?
  • To what extent are content and relational views incompatible, and are hybrid ‘compatibilist’ views of experience equally coherent or plausible?
  • Is the existence or absence of perceptual content compatible with empirical research into the underlying physiological mechanisms of perception?

Submission Details

All papers will be subject to double-blind peer review, following international standard practices. Submissions for this issue should be made through Topoi Editorial Manager, selecting ‘S.I.: Perception without representation (Locatelli/Wilson)’ as the article type.

Please save your manuscript in one of the formats supported by the system (Word, WordPerfect, RTF, TXT, LaTeX2E, TeX, Postscript, etc.), which does not include PDF. Formatting instructions for submissions can be found here (click ‘Information for Guest Editors and Authors’ on the right).

Papers must be in English and should not exceed 8,000 words, though there is no minimum length. Each submission should also include a title page containing contact details, a brief abstract and list of keywords for indexing purposes.

For further information, please email

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posted 18 Jun 2013, 07:30 by Keith Wilson   [ updated 21 Jul 2013, 09:38 ]

Welcome to my new site!

After almost a year of being officially websiteless when my previous site bit the dust with the demise of Apple’s iWeb, I thought it was about time I created a site that reflects my current philosophical research and interests. I intend to keep it updated with blog posts, drafts of papers and links that may be of interest to professional philosophers and students alike. Though my main interests lie the philosophy of mind and perception, I welcome feedback and discussion with anyone with an interest in academic philosophy, so please feel free to leave comments either here or on Twitter.

I decided to go with Google Sites as a neutral, if somewhat basic, platform for the new site. Though it lacks the sophistication and design flair of dedicated blogging platforms like WordPress and Tumblr, it contains a number of features that make it suitable for an academic or professional website, including free domain name customisation and integration with Google Docs—useful for uploading papers and the like. Unfortunately, Google Sites doesn't support user comments as standard, but I was able to add this via Disqus, a third-party add-on that fills the gap.

The contents of the site were largely taken from my existing e-portfolio at the University of Warwick, which has evolved during the course of my Ph.D. studies, but with additional room for expansion in areas I’d like to develop further. One idea I hope to explore is creating a wiki for my research, possibly including contributions from other philosophers and colleagues, which was another factor in my choice of hosting platform. (As you can see, recent changes to the site—an essential feature of any wiki—appears in the sidebar on the right.)

I'd be interested to know how other academics use their websites for research, so if you know of any particularly good examples of academics’ personal sites, or if you’d just like to say ‘hi’, please post a link or comment below.

Thanks for visiting and do drop me a line or subscribe via RSS if you’d like to keep in touch.

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