Editing Direct and indirect realism (section)

== Arguments against indirect realism ==

One concern with indirect realism is that if simple data flow and [[Information processing (psychology)|information processing]] is assumed then something in the brain must be interpreting incoming data. This something is often described as a [[homunculus]], although the term homunculus is also used to imply an entity that creates a continual [[Regress argument|regress]], and this need not be implied. This suggests that some phenomenon other than simple data flow and information processing is involved in perception. This is more of an issue now than it was for [[rationalism|rationalist]] philosophers prior to Newton, such as Descartes, for whom physical processes were poorly defined. Descartes held that there is a "homunculus" in the form of the soul, belonging to a form of natural substance known as ''[[Mental substance|res cogitans]]'' that obeyed different laws from those obeyed by solid matter (''[[res extensa]]''). Although Descartes' duality of natural substances may have echoes in modern physics (Bose and Fermi statistics) no agreed account of 'interpretation' has been formulated. Thus representationalism remains an incomplete description of perception. Aristotle realized this and simply proposed that ideas themselves (representations) must be aware—in other words that there is no further transfer of sense impressions beyond ideas.
[[Image:Rep-perception.jpg|thumb|upright=1.5|The representational theory of perception]]

A potential difficulty with representational realism is that, if we only have knowledge of representations of the world, how can we know that they resemble in any significant way the objects to which they are supposed to correspond? Any creature with a representation in its brain would need to interact with the objects that are represented to identify them with the representation. This difficulty would seem reasonably to be covered by the learning by exploration of the world that goes on throughout life. However, there may still be a concern that if the external world is only to be [[inference|inferred]], its 'true likeness' might be quite different from our idea of it. The representational realist would answer to this that "true likeness" is an intuitive concept that falls in the face of logic, since a likeness must always depend on the way in which something is considered.

A semantic difficulty may arise when considering [[reference]] in representationalism. If a person says "I see the Eiffel Tower" at a time when they are indeed looking at the Eiffel Tower, to what does the term "Eiffel Tower" refer? The direct realist might say that in the representational account people do not really see the tower but rather 'see' the representation. However, this is a distortion of the meaning of the word "see" which the representationalist does not imply. For the representationalist the statement refers to the Eiffel Tower, which implicitly is experienced in the form of a representation. The representationalist does not imply that when a person refers to the Eiffel Tower, they are referring to their [[Empirical evidence|sense experience]], and when another person refers to the Tower, they are referring to their sense experience.

Furthermore, representative realism claims that we perceive our perceptual intermediaries—we can attend to them—just as we observe our image in a mirror. However, as we can scientifically verify{{Citation needed|date=March 2021}}, this is clearly not true of the physiological components of the perceptual process. This also brings up the problem of [[mind-body dualism|dualism]] and its relation to representative realism, concerning the incongruous marriage of the metaphysical and the physical.

The new objection to the Homunculus Argument claims that it relies on a naive view of sensation.  Because the eyes respond to light rays, there is no reason for supposing that the visual field requires eyes to see it.  Visual sensation (the argument can be extrapolated to the other senses) bears no direct resemblance to the light rays at the retina, nor to the character of what they are reflected from or pass through or what was glowing at the origin of them.  The reason given is that they only bear the similarities of ''co-variation'' with what arrives at the retinas.<ref>Sellars, Roy Wood (1919), "The epistemology of evolutionary naturalism", Mind, 28:112, 407-26;  se p. 414.</ref>  Just as the currents in a wire going to a loudspeaker vary proportionately with the sounds that emanate from it but have no other likeness, so too does sensation vary proportionately (and not necessarily directly) with what causes it but bears no other resemblance to the input.  This implies that the colour we experience is actually a cortical occurrence, and that light rays and external surfaces are not themselves coloured.  The proportional variations with which cortical colour changes are there in the external world, but not colour as we experience it.  Contrary to what Gilbert Ryle believed, those who argue for sensations being brain processes do not have to hold that there is a "picture" in the brain since this is impossible according to this theory since actual pictures in the external world are not coloured.<ref>Wright, Edmond (2005), ''Narrative, Perception, Language, and Faith,'' Basingstoke:  Palgrave Macmillan, pp. 96-102.</ref> It is plain that Ryle unthinkingly carried over what the eyes do to the nature of sensation; A. J. Ayer at the time described Ryle's position as "very weak".<ref>Ayer, A. J. (1957) ''The Problem of Knowledge,'' Harmondsworth:  Penguin Books.</ref> So there is no "screen" in front of cortical "eyes", no mental objects before one. As [[Thomas Hobbes]] put it: "How do we take notice of sense?—by sense itself". Moreland Perkins has characterized it thus: that sensing is not like kicking a ball, but rather "kicking a kick".<ref>Hobbes, Thomas (1839 [1655]), ''Elements of Philosophy, The First Section: Concerning Body,'' London: John Bohn, p. 389;  Perkins, Moreland (1983), ''Sensing the World,'' Indianapolis IN: Hackett Pub. Co., pp. 286-7.</ref> Today there are still philosophers arguing for colour being a property of external surfaces, light sources, etc.<ref>Michael Tye (2006), 'The puzzle of true blue', ''Analysis,'' 66: 173-78;  Matthen, Mohan (2009), 'Truly blue:  an adverbial aspect of perceptual representation', ''Analysis,'' 69:1, 48-54.</ref>

A more fundamental criticism is implied in theories of this type. The differences at the sensory and perceptual levels between agents require that some means of ensuring at least a partial correlation can be achieved that allows the updatings involved in communication to take place.  The process in an informative statement begins with the parties hypothetically assuming that they are referring to the "same" entity or "property", even though their selections from their sensory fields cannot match; we can call this mutually imagined projection the "logical subject" of the statement.  The speaker then produces the logical predicate which effects the proposed updating of the "referent". If the statement goes through, the hearer will now have a different percept and concept of the "referent"—perhaps even seeing it now as two things and not one. The radical conclusion is that we are premature in conceiving of the external as already sorted into singular "objects" in the first place, since we only need to behave ''as if'' they are already logically singular.<ref>Wright, Edmond (2005), ''Narrative, Perception, Language, and Faith,'' Basingstoke:  Palgrave Macmillan, pp. 103-120.</ref> The diagram at the beginning of this entry would thus be thought of as a false picture of the actual case, since to draw "an" object as already selected from the real is only to treat the practically needful, but strictly false, hypothesis of objects-as-logically-singular as ontologically given. The proponents of this view thus argue that there is no need actually ''to believe'' in the singularity of an object since we can manage perfectly well by ''mutually imagining'' that 'it' is singular.  A proponent of this theory can thus ask the direct realist  why he or she thinks it is necessary to move to taking the imagining of singularity for real when there is no practical difference in the outcome in action.  Therefore, although there are selections from our sensory fields which for the time being we treat as if they were objects, they are only provisional, open to corrections at any time, and, hence, far from being direct ''representations'' of pre-existing singularities, they retain an experimental character.  Virtual constructs or no, they remain, however, selections that are causally linked to the real and can surprise us at any time—which removes any danger of solipsism in this theory.  This approach dovetails with the philosophy known as [[social constructivism]].<ref>Glasersfeld, Ernst von (1995), ''Radical Constructivism:  A Way of Knowing and Learning,'' London:  RoutledgeFalmer.</ref>