Online research in philosophy

The paper seeks a perfectly general argument regarding the non-contingent limits to any (human or non-human) knowledge. After expressing disappointment with the history of philosophy on this score, an argument is grounded in Fitch’s proof, which demonstrates the unknowability of some truths. The necessity of this unknowability is then defended by arguing for the necessity of Fitch’s premise—viz., there this is in fact some ignorance.

The knowledge argument aims to refute physicalism, the view that the world is entirely physical. The argument first establishes the existence of facts (or truths or information) about consciousness that are not a priori deducible from the complete physical truth, and then infers the falsity of physicalism from this lack of deducibility. Frank Jackson (1982, 1986) gave the argument its classic formulation. But now he rejects the argument (Jackson 1998b, 2003, chapter 3 of this volume). On his view, it relies on a false conception of sensory experience, which should be replaced with representationalism (also known as intentionalism), the view that phenomenal states are just representational states. And he argues that mental representation is physically explicable.

Yujin Nagasawa has recently defended Frank Jackson’s knowledge argument from the “inconsistency objection.” The objection claims that the premises of the knowledge argument are inconsistent with qualia epiphenomenalism. Nagasawa defends Jackson by showing that the objection mistakenly assumes a causal theory of phenomenal knowledge. I argue that although this defense might succeed against two versions of the inconsistency objection, mine is unaffected by Nagasawa’s argument, in which case the inconsistency in the knowledge argument remains.

According to the knowledge argument, physicalism fails because when physically omniscient Mary first sees red, her gain in phenomenal knowledge involves a gain in factual knowledge. Thus not all facts are physical facts. According to the ability hypothesis, the knowledge argument fails because Mary only acquires abilities to imagine, remember and recognise redness, and not new factual knowledge. I argue that reducing Mary’s new knowledge to abilities does not affect the issue of whether she also learns factually: I show that gaining specific new phenomenal knowledge is required for acquiring abilities of the relevant kind. Phenomenal knowledge being basic to abilities, and not vice versa, it is left an open question whether someone who acquires such abilities also learns something factual. The answer depends on whether the new phenomenal knowledge involved is factual. But this is the same question we wanted to settle when first considering the knowledge argument. The ability hypothesis, therefore, has offered us no dialectical progress with the knowledge argument, and is best forgotten.

I argue that the knowledge argument is best understood as an argument for the existence of non-physical properties of material objects, or colours. I suggest that the knowledge argument is standardly presented as an argument for the existence of qualia because it is implicitly assumed that physics “tell us” that what it is like to perceive colour is determined, not by properties of material objects, but by properties of perceiving subjects; hence any gaps in Mary’s knowledge must be gaps in her knowledge about perceiving subjects. If nothing else, this physicalist assumption is odd given that the knowledge argument is supposed to be an argument against physicalism. Using the knowledge argument as an argument for the existence of non-physical colours is consistent with the transparency of perceptual experience. Moreover, rejecting the physicalist assumption behind the orthodox interpretation of the knowledge argument undermines the motivation for thinking of non-physical colours as epiphenomenal.

The paper discusses whether there are strictly inexpressible properties. Three main points are argued for: (i) Two different senses of ‘predicate t expresses property p ’ should be distinguished. (ii) The property of being a predicate that does not apply to itself is inexpressible in one of the senses of ‘express’, but not in the other. (iii) Since the said property is related to Grelling’s Antinomy, it is further argued that the antinomy does not imply the non-existence of that property.

I defend Frank Jackson's knowledge argument against physicalism in the philosophy of mind from a criticism that has been advanced by Laurence Nemirow and David Lewis. According to their criticism, what Mary lacked when she was in her black and white room was a set of abilities; she did not know how to recognize or imagine certain types of experience from a first-person perspective. Her subsequent discovery of what it is like to experience redness amounts to no more than her acquisition of these abilities. The physicalist can admit this, since it does not commit one to the view that there are any facts of which Mary was ignorant (in spite of her exhaustive knowledge of truths about the physical world). I argue against this view, on the grounds that the knowledge of what an experience is like cannot be equated with the possession of any set of abilities.

The Knowability Paradox is a logical argument to the effect that, if there are truths not actually known, then there are unknowable truths. Recently, Alexander Paseau and Bernard Linsky have independently suggested a possible way to counter this argument by typing knowledge. In this article, we argue against their proposal that if one abstracts from other possible independent considerations supporting reasons for typing knowledge and considers the motivation for a type-theoretic approach with respect to the Knowability Paradox alone, there is no substantive philosophical motivation to type knowledge, except that of solving the paradox. Every attempt to independently justify the typing of knowledge is doomed to failure.

According to Frank Jackson’s famous knowledge argument, Mary, a brilliant neuroscientist raised in a black and white room and bestowed with complete physical knowledge, cannot know certain truths about phenomenal experience. This claim about knowledge, in turn, implies that physicalism is false. I argue that the knowledge argument founders on a dilemma. Either (i) Mary cannot know the relevant experiential truths because of trivial obstacles that have no bearing on the truth of physicalism or (ii) once the obstacles have been removed, Mary can know the relevant truths. If we give Mary the epistemological capabilities necessary to draw metaphysical conclusions about physicalism, she will, while trapped in the black and white room, be able to know every truth about phenomenal experience.