István Aranyosi

Tobias Hansson Wahlberg argues in a recent article (2009) that the truth of “Hesperus is Phosphorus” depends on the assumption that the endurance theory of persistence is true. The statement is not true (or at least can reasonably be doubted), he argues, if one assumes (a) the theory of persistence according to which objects are four-dimensional entities, persisting through perdurance, i.e. by having temporal parts that are numerically distinct, and (b) the thesis of unrestricted mereological composition (UMC), that is, that any two things, however scattered in space or time, compose a sum.

The dictionary tells you that a shadow is a dark area or volume caused by an opaque object blocking some light. The definition is correct, but we need to clarify a couple of its elements: darkness and blocking. The clarification leads to the view that to see a shadow is a degree of failing to see a surface. I will also argue that seeing a silhouette (i.e. a backlit object) is a particular way of failing to see an object. Thus visual discriminability is not sufficient for seeing. Finally, I argue that comparative empirical research on shadows' contribution to amodal completion in apes and humans supports the view that humans, unlike apes, perceive shadows as shadows rather than as black objects, thus lending indirect support for my view that to see a shadow is a way and degree of failing to see a surface.

In his latest book, Roy Sorensen offers a solution to a puzzle he put forward in an earlier article -The Disappearing Act. The puzzle involves various question about how the causal theory perception is to be applied to the case of seeing shadows. Sorensen argues that the puzzle should be taken as bringing out a new way of seeing shadows. I point out a problem for Sorensen’s solution, and offer and defend an alternative view, according to which the puzzle is to be interpreted as showing a new way of seeing objects, in virtue of their contrast with light

Leibniz notoriously insisted that no two individuals differ solo numero, that is, by being primitively distinct, without differing in some property. The details of Leibniz’s own way of understanding and defending the principle –known as the principle of identity of indiscernibles (henceforth ‘the Principle’)—is a matter of much debate. However, in contemporary metaphysics an equally notorious and discussed issue relates to a case put forward by Max Black (1952) as a counter-example to any necessary and non-trivial version of the principle. Black asks us to imagine, via one of the fictional characters of his dialogue, a world consisting solely of two completely resembling spheres, in a relational space. The supporter of the principle is then forced to admit that although there are ex hypothesi two objects in that universe, there is no property (except trivial ones), not even relational ones, to distinguish them, and hence the necessary version of the principle is falsified. In this essay I will argue that Black’s possible world, together with the dialectic between the potential friends and foes of the Principle as expounded by Black himself..

Ordinary people tend to be realists regarding perceptual experience, that is, they take perceiving the environment as a direct, unmediated, straightforward access to a mindindependent reality. Not so for (ordinary) philosophers. The empiricist influence on the philosophy of perception, in analytic philosophy at least, made the problem of perception synonymous with the view that realism is untenable. Admitting the problem (and trying to offer a view on it) is tantamount to rejecting ordinary people’s implicit realist assumptions as naive. So what exactly is the problem? We can approach it via one of the central arguments against realism – the argument from hallucination. The argument is intended as a proof that in ordinary, veridical cases of perception, perceivers do not have an unmediated perceptual access to the world. There are many versions of it; I propose the following1: 1. Hallucinations that are subjectively indistinguishable from veridical perceptions are possible. 2. If two subjective states are indistinguishable, then they have a common nature. 3. The contents of hallucinations are mental images, not concrete external objects. 4. Therefore, the contents of veridical perceptions are mental images rather than concrete external objects. The key move is, I believe, from the fact that hallucinations that are subjectively indistinguishable from cases of veridical perception are possible to an alleged common element, factor, or nature, in the form of a mental state, in the two cases – that is, premise 2. Disjunctivism, at its core, can be taken as simply denying this move, and arguing that all that follows from the premise stating the possibility of hallucinations that are subjectively indistinguishable from cases veridical perception is that there is a broader category, that of “experience as of...”, which encompasses both cases..