¹ Philosophers used to call representation ‘intentionality’. This term was closely associated with some bad philosophical theories, and it is easily confused with being intentional in the sense of being on purpose. So I prefer the term ‘representation’.

² Although some philosophers distinguish the kinds psychology and mind, I begin by taking them to be the same kind. The notion mind is more often associated with consciousness. The notion psychology (as in having a psychology) is more often associated with representation. Descartes is an early source of this distinction. I shall return to it at the end of the talk. Through most of the talk, however, I will not be drawing any such distinction.

³ Much of what follows in this talk is elaborated in much greater detail in my Origins of Objectivity (Oxford: Clarendon Press, 2010), chapters 8 and 9Google Scholar; and in my ‘Origins of Perception’, Disputatio 4:29 (2011), 1–38Google Scholar.

⁴ The reference here to sentences is just illustrative. Sentences have and exhibit propositional structure. I do not think that propositions are sentences, or that all propositional contents are expressed by sentences. I take the notion of propositional structure to be more basic than the notion of structure of complete sentences.

⁵ For the instrumentalist view, see Dennett, Daniel C., ‘Intentional Systems’, The Journal of Philosophy 68 (1971), 87–106CrossRefGoogle Scholar; reprinted in The Intentional Stance (Cambridge, Mass.: MIT Press, 1989)Google Scholar.

⁶ The visual system utilizes a wider range of input, not just stimuli of the retina. For example, it uses proprioceptive information about the direction and movement of the eyes. The underdetermination problem applies to the wider range as well.

⁷ Undetermination is a mathematical matter: It is logically and mathematically possible for the environmental causes of the registration of proximal stimulation (the causes that are potential objects of perception) to vary while the registration of proximal stimulation remains fixed. It is logically and mathematically possible for perceptual states to vary while a given registration of proximal stimulation remains fixed. In fact, these sorts of underdetermination are always not only logically and mathematically possible. They are also psycho-physically possible.

⁸ Most points made here occur in any mainstream textbook in visual psychology. See Palmer, Stephen E., Vision Science (Cambridge, Ma: MIT Press, 2000), 9–11, 18–24, 55-59Google Scholar; and Bruce, Vicki and Green, Patrick, Visual Perception: Physiology, Psychology, and Ecology (Hillsdale, New Jersey; Lawrence Erlbaum, 1985, 2004, 4^th edn.)Google Scholar. The real science resides in journal articles.

⁹ See Origins of Objectivity, op. cit., 419-421.

¹⁰ I cite three bodies of empirical evidence, among many others, with a sampling of relevant psychological literature.

1. (1)

   (1) There is evidence that some color constancies–hence perceptions – in bumblebees occur at the retinal level, with nearly no processing. Such constancies almost surely occur before consciousness could occur, even if the bees are conscious. Dyer, Adrian G., ‘Bumblebees Directly Perceive Variations in the Spectral Quality of Illumination’, Journal of Comparative Physiology A 192 (2006), 333–338CrossRefGoogle ScholarPubMed. There is reason to believe that similar, very primitive color constancies occur at the retinal level in humans–again, well before consciousness is likely to arise. See Vanleeuwen, M.T., Joselevitch, C., and Fahrenfort, I., ‘The Contribution of the Outer Retina to Color Constancy’, Visual Neuroscience 24 (2007), 277–290CrossRefGoogle ScholarPubMed

2. (2)

   (2) There are, in humans and other animals, certain states formed post-retinally, but in the first micro-seconds of visual processing, that seem to involve perceptual constancies, but seem not to be conscious. Again, it is likely that these constancies are formed before any kind of consciousness can occur. Such states are, at the very least, not consciously accessible. The individuals are oblivious to what they perceive. Luck, Steven J., Vogel, Edward K., and Shapiro, Kimron L., ‘Word Meanings Can Be Accessed But Not Reported During the Attentional Blink’, Nature 393 (1996), 616–618CrossRefGoogle Scholar; Dehaene, Stanislas, Naccache, Lionel, Le Clec'H, Guryan, Koechlin, Etienne, Mueller, Michael, Behaene-Lambertz, Ghislaine, van de Moortele, Pierre-Francois, and Le Bihan, Denis, ‘Imaging Unconscious Semantic Priming’, Nature 395 (1998), 597–600CrossRefGoogle ScholarPubMed; Marois, Rene, Yi, Do-Joon, and Chun, Marvin M., ‘The Neural Fate of Consciously Perceived and Missed Events in the Attentional Blink’, Neuron 41 (2004), 465–472CrossRefGoogle ScholarPubMed.

3. (3)

   (3) We know that blindsight patients perceive entities, again showing an array of perceptual constancies. It is likely that the relevant perceptions by blindsight patients are not phenomenally conscious. Blindsight is just one of many types of dissociation in which unconscious perception occurs. Prosopagnosia and extinction-neglect syndromes are others. I discuss these matters in greater depth in Origins of Objecvtivity, op. cit., esp. 374-376. For a sampling of relevant psychological literature, see Weiskrantz, L., Blindsight (New York: Oxford University Press, 1986)Google Scholar; Kentridge, R.W., Heywood, C.A., Weiskrantz, L., ‘Spatial Attention Speeds Discrimination Without Awareness in Blindsight’, Neuropsychologia 42 (2004), 831–835CrossRefGoogle ScholarPubMed; Danckert, James and Rossetti, Yves, ‘Blindsight in Action: What Can the Different Sub-types of Blindsight Tell Us about the Control of Visually Guided Actions?’, Neuroscience & Biobehavioral Reviews, 29 (2005), 1035–1046CrossRefGoogle ScholarPubMed; Schacter, Daniel L., McAndrews, Mary Pat, and Moscovitch, Morris, ‘Access to Consciousness: Dissociations between Implicit and Explicit Knowledge in Neuropsychological Syndromes’, in Thought Without Language, Weiskrantz, L. ed. (Oxford, Clarendon Press, 1989)Google Scholar; Farah, Martha J., ‘Visual Perception and Visual Analysis After Brain Damage: A Tutorial Overview’, in Umilta, C. and Moscovitch, M. eds, Attention and Performance XV: Conscious and Nonconscious Information Processing (Cambridge, Mass.; MIT Press, 1995), 37–75Google Scholar, also in Block, N., Flanagan, O., and Güzeldere, G. eds., The Nature of Consciousness (Cambridge, Mass.; MIT Press, 1998)Google Scholar. See also Volpe, Bruce T., Ledoux, Joseph E., and Gazzaniga, Michael S., ‘Visual Processing of Visual Stimuli in an ‘Extinguished’ Field', Nature 282 (1979), 722–724CrossRefGoogle Scholar; Verfaellie, M., Milberg, W.P., McGlinchey-Berroth, R., Grande, L., and D'Esposito, M., ‘Comparison of Cross-field Matching and Forced Choice Identification in Hemispatial Neglect’, Neuropsychology 9 (1995), 427–434CrossRefGoogle Scholar; Morris, James P., Pelphrey, Kevin A., and McCarthy, Gregory, ‘Face Processing Without Awareness in the Right Fusiform Gyrus’, Neuropsychologia 45 (2007), 3087–3091CrossRefGoogle ScholarPubMed.