Michael Huemer

Externalist theories of justification create the possibility of cases in which everything appears to one relevantly similar with respect to two propositions, yet one proposition is justified while the other is not. Internalists find this difficult to accept, because it seems irrational in such a case to affirm one proposition and not the other. The underlying internalist intuition supports a specific internalist theory, Phenomenal Conservatism, on which epistemic justification is conferred by appearances.

Some theories of practical reasons incorporate a lexical priority structure, according to which some practical reasons have infinitely greater weight than others. This includes absolute deontological theories and axiological theories that take some goods to be categorically superior to others. These theories face problems involving cases in which there is a non-extreme probability that a given reason applies. In view of such cases, lexical-priority theories are in danger of becoming irrelevant to decision-making, becoming absurdly demanding, or generating paradoxical cases in which each of a pair of actions is permissible yet the pair is impermissible.

Parsimony is a virtue of empirical theories. Is it also a virtue of philosophical theories? I review four contemporary accounts of the virtue of parsimony in empirical theorizing, and consider how each might apply to two prominent appeals to parsimony in the philosophical literature, those made on behalf of physicalism and on behalf of nominalism. None of the accounts of the virtue of parsimony extends naturally to either of these philosophical cases. This suggests that in typical philosophical contexts, ontological simplicity has no evidential value.

The “doctrine of the given” that Fales defends holds that there are certain experiences such that we can have justified beliefs about their “contents” that are not based on any other beliefs, and that the rest of our justified empirical beliefs rest on those “basic beliefs.” The features of experience basic beliefs are about are said to be “given.” Fales holds that some basic beliefs are infallible, having a kind of clarity that guarantees their truth to the believer. In addition, some basic beliefs are fallible, typically due to failure to devote full attention to one’s experience.

Skeptical hypotheses such as the brain-in-a-vat hypothesis provide extremely poor explanations for our sensory experiences. Because these scenarios accommodate virtually any possible set of evidence, the probability of any given set of evidence on the skeptical scenario is near zero; hence, on Bayesian grounds, the scenario is not well supported by the evidence. By contrast, serious theories make reasonably specific predictions about the evidence and are then well supported when these predictions are satisfied

Recent results in probability theory have cast doubt on the coherence theory of justification, allegedly showing that coherence cannot produce justification for beliefs in the absence of foundational justification, and that there can be no measure of coherence on which coherence is generally truth-conducive. I argue that the coherentist can reject some of the assumptions on which these theorems depend. Coherence can then be held to produce justification on its own, and truth-conducive measures of coherence can be constructed.

Ethical naturalists interpret moral knowledge as analogous to scientific knowledge and not dependent on intuition. For their account to succeed, moral truths must explain observable phenomena, and these explanations (i) must be better than any explanations framed in non-moral terms, (ii) must not rely on ad hoc posits about the causal powers of moral properties, and (iii) must not presuppose the existence of an independent means of awareness of moral truths. No moral explanations satisfy these criteria.

The _minimal free will thesis_ (MFT) holds that at least some of the time, someone has more than one course of action that he can perform. ⁽¹⁾ This is the least that must be true in order for it to be said that there is free will. It may be disputed whether the truth of MFT is _sufficient_ for us to 'have free will,' ⁽²⁾ but there is no doubt that the main philosophical challenge to the belief in free will has come from the thesis of universal determinism, so understood as to exclude MFT. A proof of MFT is therefore of considerable philosophical interest, whether or not it constitutes a full proof of free will. In any case, it is the minimal free will thesis of which I have a proof to offer.

Individuals have a prima facie right to own firearms. This right is significant in view both of the role that such ownership plays in the lives of firearms enthusiasts and of the self-defense value of firearms. Nor is this right overridden by the social harms of private gun ownership. These harms have been greatly exaggerated and are probably considerably smaller than the benefits of private gun ownership. And I argue that the harms would have to be at least several times greater than the benefits in order to render gun prohibition permissible.

In the practice of jury nullification, a jury votes to acquit a defendant in disregard of the factual evidence, on the grounds that a conviction would result in injustice, either because the law itself is unjust or because its application in the particular case would be unjust. Though the practice is widely condemned by courts, the arguments against jury nullification are surprisingly weak. I argue that, pursuant to the general ethical duty to avoid causing unjust harms to others, jurors are often morally obligated to disregard the law.

Seven proposed accounts of epistemic possibility are criticized, and a new account is proposed, making use of the notion of having justification for dismissing a proposition. The new account explains intuitions about otherwise puzzling cases, upholds plausible general principles about epistemic possibility, and explains the practical import of epistemic modality judgements. It is suggested that judgements about epistemic possibility function to assess which propositions are worthy of further inquiry.

Sense data are the alleged mind-dependent objects that we are directly aware of in perception, and that have exactly the properties they appear to have. For instance, sense data theorists say that, upon viewing a tomato in normal conditions, one forms an image of the tomato in one's mind. This image is red and round. The mental image is an example of a “sense datum.” Many philosophers have rejected the notion of sense data, either because they believe that perception gives us direct awareness of physical phenomena, rather than mere mental images, or because they believe that the mental phenomena involved in perception do not have the properties that appear to us (for instance, I might have a visual experience representing a red, round tomato, but my experience is not itself red or round). Defenders of sense data have argued, among other things, that sense data are required to explain such phenomena as perspectival variation, illusion, and hallucination. Critics of sense data have objected to the theory's commitment to mind-body dualism, the problems it raises for our knowledge of the external world, its difficulty in locating sense data in physical space, and its apparent commitment to the existence of objects with indeterminate properties

A central problem facing a probabilistic approach to the problem of induction is the difficulty of sufficiently constraining prior probabilities so as to yield the conclusion that induction is cogent. The Principle of Indifference, according to which alternatives are equiprobable when one has no grounds for preferring one over another, represents one way of addressing this problem; however, the Principle faces the well-known problem that multiple interpretations of it are possible, leading to incompatible conclusions. I propose a partial solution to the latter problem, drawing on the notion of explanatory priority. The resulting synthesis of Bayesian and inference-to-best-explanation approaches affords a principled defense of prior probability distributions that support induction

:Ideal theorists in political philosophy seek to describe a perfect political society, and to evaluate political principles by reference to their consequences in a world where everyone complies with the principles. I argue that ideal theory is not needed to set goals for practical inquiries, nor to define justice, nor to enable rankings of injustices. Nor is it useful to theorize about very different kinds of society that might occur in the far future. Ideal theory tempts us to make each of three kinds of error: it tempts us to propose norms that no specific agent can act on, to posit crazy exaggerations of moral virtues, and to place too much trust in abstract philosophical reasoning. A better approach to normative questions is to rely on analogical arguments starting from uncontroversial intuitions about concrete scenarios.