37 research outputs found
Can I kill my younger self? Time travel and the retrosuicide paradox
Abstract. If (backward) time travel is possible, presumably so is my shooting my younger self (YS); then apparently I can kill himāI can commit retrosuicide. But if I were to kill him I would not exist to shoot him, so how can I kill him? The standard solution to this paradox understands ability as compossibility with the relevant facts and points to an equivocation about which facts are relevant: my killing YS is compossible with his proximity but not with his survival, so I can kill him if facts like his survival are irrelevant but I cannot if they are relevant. I identify a lacuna in this solution, namely its reliance without argument on the hidden assumption that my killing YS is possible: if it is impossible, it is not compossible with anything. I argue that this lacuna is important, and I sketch a different solution to the paradox. 1
Against Moral Character Evaluations: The Undetectability of Virtue and Vice
Abstract. I defend the epistemic thesis that evaluations of people in terms of their moral character as good, bad, or intermediate are almost always epistemically unjustified. (1) Because most people are fragmented (they would behave deplorably in many and admirably in many other situations), oneās prior probability that any given person is fragmented should be high. (2) Because oneās information about specific people does not reliably distinguish those who are fragmented from those who are not, oneās posterior probability that any given person is fragmented should be close to oneās priorāÆand thus should also be high. (3) Because being fragmented entails being indeterminate (neither good nor bad nor intermediate), oneās posterior probability that any given person is indeterminate should also be highāÆand the epistemic thesis follows. (1) and (3) rely on previous work; here I support (2) by using a mathematical result together with empirical evidence from personality psychology. 1. Introduction: Th
Hempel`s Raven Paradox: A Lacuna in the Standard Bayesian Solution
According to Hempel`s paradox, evidence (E) that an object is a nonblack nonraven confirms the hypothesis (H) that every raven is black. According to the standard Bayesian solution, E does confirm H but only to a minute degree. This solution relies on the almost never explicitly defended assumption that the probability of H should not be affected by evidence that an object is nonblack. I argue that this assumption is implausible, and I propose a way out for the Bayesians
New foundations for imperative logic I: Logical connectives, consistency, and quantifiers
Abstract. Imperatives cannot be true or false, so they are shunned by logicians. And yet imperatives can be combined by logical connectives: ākiss me and hug me ā is the conjunction of ākiss me ā with āhug meā. This example may suggest that declarative and imperative logic are isomorphic: just as the conjunction of two declaratives is true exactly if both conjuncts are true, the conjunction of two imperatives is satisfied exactly if both conjuncts are satisfiedāÆwhat more is there to say? Much more, I argue. āIf you love me, kiss meā, a conditional imperative, mixes a declarative antecedent (āyou love meā) with an imperative consequent (ākiss meā); it is satisfied if you love and kiss me, violated if you love but donāt kiss me, and avoided if you donāt love me. So we need a logic of three-valued imperatives which mixes declaratives with imperatives. I develop such a logic. 1
In Defense of Imperative Inference
Abstract. āSurrender; therefore, surrender or fight ā is apparently an argument corresponding to an inference from an imperative to an imperative. Several philosophers, however (Williams 1963; Wedeking 1970; Harrison 1991; Hansen 2008), have denied that imperative inferences exist, arguing that (1) no such inferences occur in everyday life, (2) imperatives cannot be premises or conclusions of inferences because it makes no sense to say, for example, āsince surrender ā or āit follows that surrender or fightā, and (3) distinct imperatives have conflicting permissive presuppositions (āsurrender or fight ā permits you to fight without surrendering, but āsurrender ā does not), so issuing distinct imperatives amounts to changing oneās mind and thus cannot be construed as making an inference. In response I argue inter alia that, on a reasonable understanding of āinferenceā, some everyday-life inferences do have imperatives as premises and conclusions, and that issuing imperatives with conflicting permissive presuppositions does not amount to changing oneās mind. 1. Introduction: Imperativ
The indeterminacy paradox: Character evaluations and human psychology
Abstract. You may not know me well enough to evaluate me in terms of my moral character, but I take it you believe I can be evaluated: it sounds strange to say that I am indeterminate, neither good nor bad nor intermediate. Yet I argue that the claim that most people are indeterminate is the conclusion of a sound argumentāthe indeterminacy paradoxāwith two premises: (1) most people are fragmented (they would behave deplorably in many and admirably in many other situations); (2) fragmentation entails indeterminacy. I support (1) by examining psychological experiments in which most participants behave deplorably (e.g., by maltreating āprisoners ā in a simulated prison) or admirably (e.g., by intervening in a simulated theft). I support (2) by arguing that, according to certain plausible conceptions, character evaluations presuppose behavioral consistency (lack of fragmentation). Possible reactions to the paradox include: (a) denying that the experiments are relevant to character; (b) upholding conceptions according to which character evaluations do not presuppose consistency; (c) granting that most people are indeterminate and explaining why it appears otherwise. I defend (c) against (a) and (b)
Gigerenzer's normative critique of Kahneman and Tversky
Gigerenzer has argued that it may be inappropriate to characterize some of the biases identified by Kahneman and Tversky as "errors" or "fallacies," for three reasons: (a) according to frequentists, no norms are appropriate for single-case judgments because single-case probabilities are meaningless; (b) even if single-case probabilities make sense, they need not be governed by statistical norms because such norms are "content-blind" and can conflict with conversational norms; (c) conflicting statistical norms exist. I try to clear up certain misunderstandings that may have hindered progress in this debate. Gigerenzer's main point turns out to be far less extreme than the position of "normative agnosticism" attributed to him by Kahneman and Tversky: Gigerenzer is not denying that norms appropriate for single-case judgements exist, but is rather complaining that the existence and the nature of such norms have been dogmatically assumed by the heuristics and biases literature. In response to this complaint I argue that single-case probabilities (a) make sense and (b) are governed b
What time travelers may be able to do
Abstract. Kadri Vihvelin, in āWhat time travelers cannot do ā (1996), argued that āno time traveler can kill the baby who in fact is her younger selfā, because (V1) āif someone would fail to do something, no matter how hard or how many times she tried, then she cannot do itā, and (V2) if a time traveler tried to kill her baby self, she would always fail. Theodore Sider (2002) criticized Vihvelinās argument, and Ira Kiourti (2008) criticized both Vihvelinās argument and Siderās critique. I present a critique of Vihvelinās argument different from both Siderās and Kiourtiās critiques: I argue in a novel way that both V1 and V2 are false. Since Vihvelinās 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. 1