Ulrich Meyer

This paper argues that modal realism has a problem with mathematical impossibilities. Due to the peculiar way it treats both propositions and mathematical objects, modal realism cannot distinguish the content of different mathematically impossible beliefs. While one might be happy to identify all logically impossible beliefs, there are many different mathematically impossible beliefs, none of which is a belief in a logical contradiction. The fact that it cannot distinguish these beliefs speaks against adopting modal realism.

Many philosophers believe there to be a fundamental difference between the present and past and future times, but they tend to disagree amongst themselves about what this difference is. Some think that the present is singled out by consciousness, while others believe that it marks the position to which the flow of time has advanced. According to presentism, the current moment is ontologically privileged: nothing exists that is not present. My aim in this chapter is to argue that this particular attempt at distinguishing the present from other times is unsuccessful.

A perennial question in the philosophy of time concerns the relation between the objective “physical time” that features in empirical theories of motion and the subjective “human time” in which our own experiences unfold. This article is about one facet of this broader question: whether the phenomenon of consciousness allows us to make a principled distinction between the present and other times. A number of authors have argued that, without conscious observers, there would be no distinctions of past, present, and future. This paper defends the opposing thesis that there is no interesting connection between consciousness and presentness.

According to Hans Kamp and Frank Vlach, the two-dimensional tense operators “now” and “then” are ineliminable in quantified tense logic. This is often adduced as an argument against tense logic, and in favor of an extensional account that makes use of explicit quantification over times. The aim of this paper is to defend tense logic against this attack. It shows that “now” and “then” are eliminable in quantified tense logic, provided we endow it with enough quantificational structure. The operators might not be redundant in some other systems of tense logic, but this merely indicates a lack of quantificational resources and does not show any deep-seated inability of tense logic to express claims about time. The paper closes with a brief discussion of the modal analogue of this issue, which concerns the role of the actuality operator in quantified modal logic

Instead of accepting instants of time as metaphysically basic entities, many philosophers regard them as abstractions from something else. There is the Russell-Whitehead view that times are maximal classes of simultaneous events; the linguistic ersatzer's proposal that times are maximally consistent sets of sentences or propositions; and the view that times are made up of temporal parts of material objects. This paper discusses the advantages and disadvantages of these various proposals and concludes in favor of a particular version of linguistic ersatzism about time.