By any reasonable reckoning, Gottlob Frege's ‘On Sense and Reference’ is one of the more important philosophical papers of all time. Although Frege briefly discusses the sense-reference distinction in an earlier work (‘Function and Concept,’ in 1891), it is through ‘Sense and Reference’ that most philosophers have become familiar with it. And the distinction so thoroughly permeates contemporary philosophy of language and mind that it is almost impossible to imagine these subjects without it.

The distinction between the sense and the referent of a name is introduced in the second paragraph of ‘Sense and Reference.’

Does natural selection explain why individual organisms have the traits that they do? This question has been the subject of vigorous debate in recent philosophy of biology. Sober and Walsh have defended the thesis that natural selection does not explain why any individual organism has the traits that it does. This thesis, I shall call ‘the Negative View.’ Neander and Matthen have defended the contrary thesis, which I shall call ‘the Positive View,’ according to which natural selection at least sometimes does explain why an individual organism has the traits that it does. In this paper, I will argue that recent arguments for the Positive View fail for a reason hitherto unnoticed and I will demonstrate that other recent defenses of the Negative View depend upon my own for their plausibility.

I begin, in Section II, by showing that the issue is whether or not natural selection explains, of an individual, why it has the traits it does.

According to Anselm's official definition, freedom of choice is ‘the power to preserve rectitude of will for the sake of that rectitude itself.’ From the point of view of contemporary metaphysics, this is one of the most unhelpful definitions imaginable. Does such freedom require alternative possibilities, for example? Is it compatible with causal determination? Is the exercise of such freedom a necessary and sufficient condition for moral responsibility? The definition sheds no light on these questions.

And so we need to move on from Anselm's definition to Anselm's account of freedom. Here, though, we encounter the opposite problem. Where Anselm's definition seems not to answer these questions at all, Anselm's account seems to answer all these questions, sometimes with a yes and sometimes with a no. Consider the question about alternative possibilities. In De libertate arbitrii, Anselm seems clearly to deny that freedom involves alternative possibilities. God, the good angels, and the blessed dead cannot do otherwise than preserve rectitude, but they are still free- freer, in fact, than those who are capable of abandoning rectitude.