This is a survey of the development of the philosophy of perception over the past twelve years. There are four sections. Part I deals largely with arguments for the propositionalizing of perception and for those types of externally founded realism that eschew inner representation. Part ii is devoted to three books that put the case for sense-Data (pennycuick, Jackson, Ginet) and some of the arguments against (pitcher). Part iii outlines james j gibson's psychological theory. Part iv takes up the arguments (...) for a theory of 'dual coding', Combining a non-Epistemic inner presentation as a first stage with epistemic selection as an independent module. The mental-Image argument (kosslyn, Pylyshyn) and wittgenstein's remarks on psychology, Recently published, Are brought in as relevant to this issue. (edited). (shrink)
These essays in the philosophy of perception cover a variety of topics, among which are included science, souls and sense-data, perception and scepticism, the causal representation theory of perception, semantic presence, the impact of contemporary neuroscience and hypothesis and illusion.
A sensory receptor, in any organism anywhere, is sensitive through time to some distribution - energy, motion, molecular shape - indeed, anything that can produce an effect. The sensitivity is rarely direct: for example, it may track changes in relative variation rather than the absolute change of state (as when the skin responds to colder and hotter instead of to cold and hot as such); it may track differing variations under different conditions (the eyes' dark-adaptation; adaptation to sound frequencies can (...) lower the difference threshold; the kinesthetic sense will shut down if a limb is held in a stationary position too long - the limb 'going to sleep'); it may be subject to distortion of the input from overloading (dazzle producing strong-after-images); it may not be confined to one channel of sensitivity (the retina is sensitive to pressure; the hands can feel some strong sound-vibrations, the tympanum of the ear records touch). Strictly speaking there is no limit as to what intensities and what ranges receptors could be sensitive. Sharks are sensitive to electrostatic fields, homing pigeons to magnetic fields; snakes to infra-red rays; bacteria to acid concentrations; perhaps there has even been a mutant organism sensitive to the passage of cosmic rays, even though that would hardly have bestowed any conceivable survival value. What is irrefutable is that individual receptors differ markedly from organism to organism, between different members of the species (one dog being better at tracing smells than another; one person being able to sense light-waves of 375 nanometres, another not; children able to hear 20,000 Hz, older persons not), and between receptors of the same kind within one organism (one eye being sensitive to 765 nm and the other not; one ear deaf to 15,000 Hz and over, the other not). There are also just-noticeable-differences (JND's), in that one person can see two shades of a colour where another sees only one; similarly with sounds. (shrink)
If a sensory field exists as a pure natural sign open to all kinds of interpretation as _evidence_ (see 'Sensing as non-epistemic'), what is it that does the interpreting? Borrowing from the old Gestalt psychologists, I have proposed a gestalt module that picks out wholes from the turmoil, it being the process of _noticing_ or _attending to_ , but the important difference from Koffka and Khler (Koffka, 1935; Khler, 1940), the originators of the term 'gestalt' in the psychology of perception (...) ( is that the emphasis is upon the gestalt projection as motivated . Gestalt-attention of this kind is usually enforced in the first instance by pain or pleasure, and the resulting projections are placed in memory tabbed with fear or desire, such that if such a pattern recurs in the sensory field, fear or desire are triggered. In advanced animals the ability to play with the gestalt module has been evolved, because experimenting in curiosity has proved adaptive, as the exploratory behaviour in the Rat, the Raven, the Apes and _Homo sapiens_ bears out. (shrink)