Zhiwei Gu

One crucial premise in the argument from illusion is the Phenomenal Principle. It states that if there sensibly appears to be something that possesses a sensible quality, then there is something of which the subject is aware that has that sensible quality. The principle thus enables the inference from a mere appearance to an existence (usually a mental one). In the argument from appearance, a similar move is taken by some philosophers—they infer a content from a mere appearance. There are two kinds of defences for the Phenomenal Principle in the literature, namely, the epistemological one (e.g. H.H. Price) and the semantic one (e.g. Frank Jackson). I argue that neither consolidates the Phenomenal Principle. I particularly demonstrate that the appearance verb in premise 1 of the argument from illusion is not used in the phenomenal sense as it is used in the Phenomenal Principle, which renders the argument essentially invalid. To avoid invalidity, the proponents either give up the phenomenal use, which makes the argument unable to serve its original purpose, i.e. inferring an unusual existence, or they insist on the phenomenal use in all premises of the argument, which will trivialise the argument. I also demonstrate that a similar objection applies to the argument from appearance.

The argument from appearance for the content view or intentionalism attracts a lot of attention recently. In my paper, I follow Charles Travis to argue against the key premise that representational content can be ‘read off’ from a certain way that a thing looks to a subject. My arguments are built upon Travis’s original objection and a reinterpretation of Rodrick Chisholm’s comparative and noncomparative uses of appearance words. Byrne, Schellenberg and others interpret Travis’ ‘visual looks’ as Chisholm’s comparative use, and appeal to the noncomparative use as an alternative to avoid Travis’s objection. I demonstrate that they misunderstand both Chisholm and Travis. Both the comparative use and the noncomparative use are semantic notions, while ‘visual looks’ is a metaphysical one. Although Chisholm’s appearance objectivism –– that appearance expressions attribute appearances to ordinary objects –– is close to ‘visual looks’, appearance objectivism is not exceptional to the noncomparative use as Byrne interprets. In the end, I also show that Byrnean’s conception of distinctive visual gestalt cannot exclude contrary representational contents, because a distinctive visual gestalt can be shared by different kinds of things. Besides, Byrne and others do not explain why a distinctive visual gestalt should be presented as ‘being instantiated’. Therefore, I conclude that representational content cannot be read off from a certain way that a thing looks to a subject; the argument from appearance thus fails.

This paper aims at offering a new disjunctivist solution – anomalous disjunctivism – to the screening-off problem. Anomalous disjunctivism focuses on the necessary causal conditions for perception and hallucination. It argues that the proximate cause is contingent on causing a particular kind of sensory experience that can either be perceptual or hallucinatory. It further shows that the perceived thing is a necessary causal condition for perceptual experience and the failure of perception is a necessary causal condition for the hallucinatory counterpart. It is the case that any account of a hallucinatory experience relies on the nature of hallucination, and, therefore, the anti-naïve realist has to agree that the necessary causal condition matters. As a consequence, whatever account we take for a hallucination, it need not apply to its perceptual counterpart. The screening-off problem, thereby, is dissolved.

The time-lag argument seems to put some pressure on naïve realism to agree that seeing must happen simultaneously with what is seen; meanwhile, a wide-accepted empirical fact suggests that light takes time to transmit from objects at a distance to perceivers—which implies what is seen happened before seeing, and, accordingly, naïve realism must be false. In this paper, I will, first of all, show that the time-lag argument has in fact involves a misunderstanding concept of simultaneity: according to Special Relativity, simultaneity is a matter of convention rather than a matter of fact, so, in principle, we can stipulate a perceptual conception of simultaneity, according to which what is seen is simultaneous with seeing. Secondly, the generalized time-lag argument has a mistaken view on the perceived events and perceiving; it has a doubtful assumption that these events are momentary in the mathematical sense. Such idealization is the main reason why we have the intuition that the time-lag effect of perceiving is in conflict with our ordinary perceptual experiences. Finally, I argue that the naïve realist account of the perceptual relation is a nontemporal constitutive relation; and hence naïve realism is compatible with the claim that we can perceive things as they were, and it should not be weakened by the time-lag argument.