Peter Vranas

David Lewis (1980) proposed the Principal Principle (PP) and a “reformulation” which later on he called ‘OP’ (Old Principle). Reacting to his belief that these principles run into trouble, Lewis (1994) concluded that they should be replaced with the New Principle (NP). This conclusion left Lewis uneasy, because he thought that an inverse form of NP is “quite messy”, whereas an inverse form of OP, namely the simple and intuitive PP, is “the key to our concept of chance”. I argue that, even if OP should be discarded, PP need not be. Moreover, far from being messy, an inverse form of NP is a simple and intuitive Conditional Principle (CP). Finally, both PP and CP are special cases of a General Principle (GP); it follows that so are PP and NP, which are thus compatible rather than competing.

I was quite excited when I first read Restall and Russell’s (2010) paper. For two reasons. First, because the paper provides rigorous formulations and formal proofs of implication barrier theses, namely “theses [which] deny that one can derive sentences of one type from sentences of another”. Second (and primarily), because the paper proves a general theorem, the Barrier Construction Theorem, which unifies implication barrier theses concerning four topics: generality, necessity, time, and normativity. After thinking about the paper, I am satisfied with its treatment of the first three topics, namely generality, necessity, and time. But I am not satisfied with its treatment of normativity, so my comments are exclusively on that topic.

Kadri Vihvelin, in "What time travelers cannot do" (Philos Stud 81: 315-330, 1996), argued that "no time traveler can kill the baby who in fact is her younger self, because (V1) "if someone would fail to do something, no matter how hard or how many times she tried, then she cannot do it", and (V2) if a time traveler tried to kill her baby self, she would always fail. Theodore Sider (Philos Stud 110: 115-138, 2002) criticized Vihvelin's argument, and Ira Kiourti (Philos Stud 139: 343-352, 2008) criticized both Vihvelin's argument and Sider's critique. I present a critique of Vihvelin's argument different from both Sider's and Kiourti's critiques: I argue in a novel way that both V1 and V2 are false. Since Vihvelin's argument might be understood as providing a challenge to the possibility of time travel, if my critique succeeds then time travel survives such a challenge unscathed

We can distinguish two concepts of respect for persons: appraisal respect , an attitude based on a positive appraisal of a person's moral character, and recognition respect , the practice of treating persons with consideration based on the belief that they deserve such treatment. After engaging in an extended analysis of these concepts, I examine two "truisms" about them. We justifiably believe of some persons that they have good character and thus deserve our esteem . Frequently it pays to be disrespectful; e.g., insulting those who insult us may put them in their place. By using empirical results from social and personality psychology and techniques from decision theory in addition to conceptual considerations, I argue that, surprisingly, the above two "truisms" are false. Extensive psychological evidence indicates that most persons are indeterminate---overall neither good nor bad nor intermediate---and that our information about specific persons almost never distinguishes those who are indeterminate from those who are not. The strategy of habitually avoiding disrespectful behavior maximizes long-term expected utility. In sum, we have good pragmatic reason to treat persons respectfully, but we have good epistemic reason to avoid esteeming or despising them