Online research in philosophy

Although Pessoa et al. imply that many aspects of the filling-in debate may be displaced by a regard for active vision, they remain loyal to naive neural reductionist explanations of certain pieces of psychophysical evidence. Alternative interpretations are provided for two specific examples and a new category of filling-in (of visual detail) is proposed.

Dispostions, such as solubility, cannont be reduced to categorical properties, such as molecular structure, without some element of dipositionaity remaining. Democritus did not reduce all properties to the geometry of atoms - he had to retain the rigidity of the atoms, that is, their disposition not to change shape when a force is applied. So dispositions-not-to, like rigidity, cannot be eliminated. Neither can dispositions-to, like solubility.

Several philosophers of science and metaphysicians claim that the dispositional properties of fundamental particles, such as the mass, charge, and spin of electrons, are ungrounded in any further properties. It is assumed by those making this argument that such properties are intrinsic, and thus if they are grounded at all they must be grounded intrinsically. However, this paper advances an argument, with one empirical premise and one metaphysical premise, for the claim that mass is extrinsically grounded and is thus an extrinsic disposition. Although the argument concerns mass characterized as a disposition, it applies equally well whether mass is a categorical or dispositional property; however, the dispositional nature of mass is relevant to some important objections and implications discussed.

A few findings from our laboratory are provided as evidence favoring “isomrphism” in filling-in. One is the responsivity of macaque-cortical area V1 cells to a stimulus designed for surface filling-in at the blind spot. Another is a phenomenological observation of motion aftereffect confined within a filled-in surface at the blind spot. Our recent study on the monkey's perception of surface filling-in at a scotoma is also mentioned.

Attempts to capture the distinction between categorical and dispositional states in terms of more primitive modal notions – subjunctive conditionals, causal roles, or combinatorial principles – are bound to fail. Such failure is ensured by a deep symmetry in the ways dispositional and categorical states alike carry modal import. But the categorical/dispositional distinction should not be abandoned; it underpins important metaphysical disputes. Rather, it should be taken as a primitive, after which the doomed attempts at reductive explanation can be transformed into circular but interesting accounts.

Implicit and explicit filling-in phenomena should be distinguished. Blind spot phenomena and mechanisms of boundary completion can be accounted for by implicit filling-in. Surface regions are “painted” with perceptual quantities, such as brightness, by explicit filling-in. “Filling-in” and “finding-out” relate to different computational tasks. Mechanisms of purposive computation (e.g., for navigation) evaluate local measurements, thus “finding out”; whereas mechanisms for grasping might require passive reconstruction, thus “filling in.”.

I develop a new theory of properties by considering two central arguments in the debate whether properties are dispositional or categorical. The first claims that objects must possess categorical properties in order to be distinct from empty space. The second argument, however, points out several untoward consequences of positing categorical properties. I explore these arguments and argue that despite appearances, their conclusions need not be in conflict with one another. In particular, we can view the second argument as supporting only the claim that there is not a plurality of categorical properties, and not the stronger claim that there are no categorical properties whatsoever. I then develop a new account of properties which capitalizes on this insight.

One of the things you learn if you read books and articles in (or about) cognitive science is that the brain does a lot of "filling in"--not filling in, but "filling in"--in scare quotes. My claim today will be that this way of talking is not a safe bit of shorthand, or an innocent bit of temporizing, but a source of deep confusion and error. The phenomena described in terms of "filling in" are real, surprising, and theoretically important, but it is a mistake to conceive of them as instances of something being filled in, for that vivid phrase always suggests too much--sometimes a little too much, but often a lot too much. Here are some examples (my boldface throughout).

A disposition mask is something that prevents a disposition from manifesting despite the occurrence of that disposition’s characteristic stimulus, and without eliminating that disposition. Several authors have maintained that masks must be things extrinsic to the objects that have the masked dispositions. Here it is argued that this is not so; masks can be intrinsic to the objects whose dispositions they mask. If that is correct, then a recent attempt to distinguish dispositional properties from so-called categorical properties fails.