It is relatively common for philosophers to doubt whether we have any reason to act as morality requires. But it is very difficult to find philosophers who are willing to doubt, in a similar way, the idea that we have reason to act as instrumental rationality requires; reason, that is, to take effective steps toward attaining the ends we have accepted as our own. The inference from the fact that a certain action is an effective means of satisfying an agent's ends to the conclusion that that agent has reason to perform that action is held by almost everyone to be, as it is sometimes said, automatic:once it is determined that the action in question bears the specified relation to one's goals, nothing more needs to be shown. But fewer philosophers are willing to grant that morality possesses this sort of automatic reason-giving force. Rather, it is quite commonly held that some additional consideration needs to be cited in order to show that an agent has reason to act as she is morally required. The fact that an action is morally required, claim those who adhere to this type of position, is not enough in itself.

Although Descartes presents himself as an adversary of skepticism, in contemporary epistemology he is celebrated much more for his presentation of the skeptical problem than for his efforts to solve it. The ‘Cartesian skepticism’ of the evil genius argument remains a Standard starting point for current discussions, a starting point that is seen (by contextualists, for example) to provide such a powerful challenge to knowledge that while one as much as contemplates such arguments one loses the right to ascribe knowledge to anyone. Even Descartes's less radical skeptical arguments are still widely credited as having tremendous force: Barry Stroud, for example, argues at length that no satisfactory response has yet been given to the dream argument of the First Meditation. The Cartesian response to skepticism, on the other hand, is not nearly so warmly received. In the current literature on skepticism one does not find much resistance to Stroud's assessment of the Cartesian response to skepticism as utterly unpromising, nor to his diagnosis of its central fault: the Cartesian response depends on a series of theological claims that Descartes does not (or perhaps cannot) show to be plausible, let alone true.

In both popular and technical discussion we often find the pairs of opposed terms ‘innate/acquired,’ ‘due to genes/due to environment,’ ‘nature/nurture,’ and so forth. They appear to be used as if they all captured a genuine distinction, and the same distinction at that. A related family of opposed pairs is held to describe the difference between those who attribute a certain trait to ‘nature’ and those who attribute it to ‘nurture’: ‘nativists’ versus ‘constructivists’ is one such pair. Chomsky and his followers are often described as ‘nativists’ regarding certain features of language. On a cursory examination, many of the claims of Evolutionary Psychology bear the appearance of ‘nativism.’ That is, it looks as though Evolutionary Psychologists are making claims to the effect that many features of the mind which are often thought to be due to ‘nurture’ are in fact due to ‘nature.’ However, two of the genre's leading practitioners, John Tooby and Leda Cosmides, vigorously deny that this is their position.

This paper explores the conceptual dimension in theory acceptance, throws light on the notion of coherence between theories, and emphasizes the role of coherence between theories in theory acceptance. It is important, however, to recognize that the empirical-conceptual distinction, like most other distinctions in philosophy, is only pragmatic because purely empirical or conceptual notions in science are rare. That is, the term ‘conceptual’ is actually used in the sense of ‘mostly conceptual’, and the term ‘empirical’ signifies what is predominantly empirical. Yet it is useful in many contexts to speak of conceptual and empirical merits of theories separately. Among the commonly discussed conceptual merits of a theory are internal consistency, simplicity, comprehensiveness, and coherence with existing theories. Empirical merits include accommodating known evidence and passing experimental tests. The focus of this paper is coherence between theories.