“Marking the Mental: Argument for the Unconscious from Leibniz to Freud,” (draft in progress)

Oxford Philosophical Concepts: Editor of the volume on Consciousness

The term “consciousness” means many things to many people (and indeed many things to any given person). And it has always been like that. A mere 50 years after Cudworth introduced of the term into philosophical English in 1678, philosophers disentangled no fewer than five distinct senses of it! Why is consciousness such a messy concept? Here’s a hypothesis that may guide this volume: consciousness has long been a “service concept,” that is a concept that is wheeled in to solve some other pressing philosophical problem (the distinction between mind and body, the immortality of the soul, personal identity, self-knowledge, the nature of intentionality, moral responsibility, and so on). If it the concept of consciousness has indeed historically been a service concept, its wild ambiguity may be less surprising: depending on the work it is being invoked to do, different aspects of conscious experience (giving rise to different sub-concepts) are inevitably going to be highlighted.



in The Cambridge Descartes Lexicon, ed. Larry Nolan (Cambridge: Cambridge University Press, forthcoming).

An overview of the concept of representation in Descartes’ work. The entry covers (a) the epistemology of mental representation (Was Descartes a “direct realist” or “indirect” realist, and what role do “ideas” play in his theory of mind?), (b) the scope of representation in the Cartesian mind (Are all mental states in the Cartesian mind representational?), and (c) the metaphysics of mental representation (How do mental states represent?) with particular attention to sensations and passions.

“Re-Humanizing Descartes”

forthcoming in Philosophic Exchange.

Looks at two “Cartesian” theses that seem to the modern mind to be disturbingly de-humanizing: mind-body dualism and the quest for Objective Knowledge. Together these theses suggest a goal of disembodied minds seeking knowledge form no particular point of view. My aim is to re-humanize the Cartesian project by situating these alienating theses in the context of Descartes treatment of the human being.

“Sensory Perception of Bodies: Meditation 6.5”

in The Cambridge Companion to Descartes’ Meditations, ed. David Cunning (Cambridge: Cambridge University Press, 2014): 258-276.

Begins with a brief guided tour of Descartes’ Meditations that highlights the epistemic unraveling of the senses from Meditation 1 to Meditation 6.5. Half way through Meditation 6, Descartes pauses to re-examine the senses in the light of the fact that they are part of a nature given to him by a non-deceiving God. They can’t be all bad. The second half of Meditation 6 is devoted to re-habilitating the senses, an endeavor which involves re-casting them as critical guides to survival. The remainder of the paper explores this re-purposing of the senses in his treatment of bodily awareness, so-called “secondary-quality” perception, and spatial perception. In the end, there is a division of cognitive labor in the cognitive economy of the Cartesian mind: the intellect is our best guide to metaphysics; the senses are our best guides to life and action.

“Perception in Early Modern Philosophy”

in the Oxford Handbook of Philosophy of Perception,” ed. Mohan Matthen (Oxford: Oxford University Press), Forthcoming 2013.

An overview of several of the leading issues discussed among early modern philosopher-scientists concerning sensory perception. These include: (a) the primary-secondary quality distinction; (b) the nature and details of sensory processing; (c) the structure of sense perceptual experience; (d) the place of “ideas” in accounts of sensory perception; and (e) sensory epistemology.

“Cartesian Consciousness Reconsidered”

in Philosophers’ Imprint 12(2) (January 2012): 1-21.

Descartes (in)famously revolutionized our conception of the mind by identifying consciousness as the mark of the mental: all and only thoughts are conscious. Today the idea that all thoughts are conscious sees hopelessly naïve or blindly dogmatic. Empirical psychologists, psychiatrists, and zombie-loving philosophers all embrace the existence, or at least the possibility, of unconscious thoughts. But Descartes faces a problem more serious than being snubbed by today’s intellectuals: in his own work on the mind, Descartes himself seems to posit a whole host of unconscious thoughts. Something is not as it seems. Either Descartes is remarkably inconsistent, or his claim that all thought is conscious is more nuanced than it appears. In this paper I argue that while Descartes was indeed unwavering in his commitment to the conscious mark, he distinguished different types and degrees of consciousness that make for a rather rich cognitive psychology, one that is capable of accommodating a range of phenomena that others might be tempted to identify as unconscious.

“Leibnizian Consciousness Reconsidered”

in Studia leibnitiana 43(2) (2011): 196-215.

Explores one conception of consciousness in Leibniz, viz., the form of external world consciousness that we share with animals. Larry Jorgensen has argued that Leibnizian external world consciousness is a first-order mental property that consists in (sufficient) perceptual distinctness.  While I (now) agree that this form of consciousness in Leibniz is not a higher-order property, I argue that it does not consist in perceptual distinctness.  It consists rather in a trans-temporal property of a mental state that Leibniz identifies as a kind of memory.  Consciousness, in short, takes time.  We might think of it as working memory that keeps perceptions active long enough to be joined with other co-present and recently past perceptions to create a unified experience of the world.

“Sensation in the Malebranchean Mind”

in Topics in Early Modern Theories of Mind, Studies in the History and Philosophy of Mind 9, edited by Jon Miller (Springer Press, 2009): 105-129.

Explores the roles of intentionality and consciousness in Malebranche’s conception of mind by looking closely at his account of sensory perception. I argue that Malebranche was not the first early modern philosopher to break with the view that intentionality is a mark of the mental, as many have supposed, but that he does introduce an interesting distinction between intentionality and representationality and harsh judgment on the epistemic credentials of consciousness. The key to all this is his account of sensory perception, which I argue has been largely misunderstood.

“Guarding the Body: A Cartesian Phenomenology of Perception”

in Contemporary Perspectives on Early Modern Philosophy: Essays in Honor of Vere Chappell, edited by Paul Hoffman and Gideon Yaffe (Broadview Press, 2008).

Although Descartes and Malebranche both routinely criticize the senses for misrepresenting the material world to us, they just as routinely insist that the senses represent the material world in a way that is especially conducive to self-preservation. What is it about sensory representation that is supposed to make it so conducive to self-preservation? And why do these thinkers suggest that the senses can do a better job of this than even their cherished intellects?

“Spatial Perception from a Cartesian Point of View”

in Philosophical Topics, vol. 31 (2003): 395-423.

Descartes’ proposal in the Sixth Meditation that sensory perception serves as a guide for self-preservation is typically taken to be an ad hoc way of finding a place for secondary quality sensations and bodily sensations. Malebranche, I argue, understands the proposal to be a way of re-conceiving sensory experience as a whole, spatial perception included. This paper examines Malebranche’s case for maintaining that spatial perception is directed to self-preservation. As I interpret it, his argument turns on the fact that spatial perception has a bodily phenomenology; that is, it represents the spatial properties of objects in a way that involves the perceiver’s own body. First, it represents objects egocentrically, as they are spatially related to the perceiver’s own body. Second, bodily awareness often figures into spatial perception. Third, the representational limits of spatial perception reflect the bodily processes on which it depends. All three of these facts about spatial representation through the senses pose problems, from a Cartesian point of view, for the natural philosopher seeking an accurate depiction of the material world. All three, however, prove advantageous to the human being trying to survive in that world.

“Descartes on the Cognitive Structure of Sensory Experience”

in Philosophy and Phenomenological Research, vol. 67, no. 3 (2003): 549-579.

Descartes is often thought to bifurcate sensory experience into two distinct cognitive components: the sensing of secondary qualities and the more or less intellectual perceiving of primary qualities. A closer examination of his analysis of sensory perception in the Sixth Replies and of his treatment of sensory processing in the Dioptrics and Treatise on Man tells a different story. I argue that Descartes offers a unified cognitive account of sensory experience according to which the senses and intellect operate together to produce a fundamentally imagistic representation of the world in both its primary and secondary quality aspects. At stake here is not only our understanding of the cognitive structure of sensory experience, but the relation between sense and intellect more generally in the Cartesian mind. The deep bifurcation in the Cartesian mind, I argue, is not between the sensory perception of primary and secondary qualities but between sensory perception and purely intellectual perception.

“Changing the Cartesian Mind: Leibniz on Sensation, Representation and Consciousness”

in The Philosophical Review, vol. 110, no. 1 (January 2001). Reprinted in The Philosopher’s Annual, vol. 24 (2002): 195-236.

Examines the overlooked but important tension between the Cartesians and Leibniz over the nature of mentality and the structure of the mind. According to the Cartesians, the distinctive mark of the mental is consciousness: all mental states are thus conscious, but, according to some Cartesians, they may not represent anything. Leibniz, by contrast, argues that the mark of the mental is representation of a special sort: all mental states are thus representational, but they may not be conscious. This fundamental difference in conception of the nature of the mental is reflected in their respective accounts of sensation, which I explore in the second half of the paper, focussing on the Leibnizian account.

“Sensible Ends: Latent Teleology in Descartes’ Account of Sensation”

in Journal of the History of Philosophy, vol. 39 (2001): 49-75.

Examines the use of teleological explanation in Descartes’ account of sensory perception. In the first half, I argue that Descartes advocates a genuinely teleological conception of the senses. In so doing, I reject familiar attempts to discharge the teleology. In the second half, I examine Descartes’ famous proscription against teleology and argue that it is not a sweeping assault on finality, but a more directed attack on particular uses of ends in natural philosophy. The proscription leaves standing a form of teleological explanation that proves crucial to Descartes’ own treatment of sensory perception.

“Are Cartesian Sensations Representational?”

in Noûs, vol. 33 (1999): 347-369.

Takes on the question whether, what and how secondary quality sensations and bodily sensations represent anything in the corporeal world in the context of Descartes’ theory of sensory perception. I argue that Descartes has pressing philosophical motivation to argue that these sensations do indeed represent something in the corporeal world; they are more than mere window dressing of the mind. In response to the pressure, Descartes offers the beginnings of what I call a “bio-functional” account of sensory representation that builds on his claim in the Sixth Meditation that the senses are directed to self-preservation.


“Jesuit Aristotelian Education: The De anima Commentaries”

in The Jesuits: Culture, Learning and the Arts, 1540-1773, edited by John W. O’Malley, S.J., Gauvin Alexander Bailey, Steven J. Harris, and T. Frank Kennedy (Toronto Univ. Press, 1999).

Explores the interpretive strategy that 16th century Jesuit philosopher used in approaching the works of Aristotle, namely, a strong form of rational reconstruction. I examine the way rational reconstruction is used in developing three components of the their Aristotelian theory of sensory cognition: (a) the role of sensible species, (b) the relative activity and passivity of the senses and (c) the role of the agent intellect.

“The Sensory Act: Descartes and the Jesuits on the Efficient Cause of Sensation”

in Meeting of the Mind: The Relations Between Medieval and Classical Modern European Philosophy, ed. Stephen F. Brown (Brepols, 1998): 63-76.

Challenges the received view that the late scholastic Aristotelians and Descartes are agreed that the senses are passive faculties. While they agree, I argue, they agree that the senses are partly passive and partly active in sensory experience. A close examination of the passive and active roles of the senses reveals a persistent division in explaining the intentionality of sensory experience on the one hand and the consciousness of it on the other.

“Explaining Sense Perception: A Scholastic Challenge”

in Philosophical Studies, vol. 73 (1994): 257-275.

Explores the philosophical foundations of the “species” theory of sensory perception as develops in late scholastic (16th c.) Jesuit philosophers. I argue that the species theory is a philosophically and textually well-motivated interpretation (and development) of Aristotle’s cryptic claim that sensory perception occurs by the “reception of form with its matter.”

NOTE: The published and forthcoming papers in this section are penultimate versions---there may be slight discrepancies between the versions here and the official ones. Please cite the published versions where available.