David Armstrong's book is a contribution to the philosophical discussion about possible worlds. Taking Wittgenstein's Tractatus as his point of departure, Professor Armstrong argues that nonactual possibilities and possible worlds are recombinations of actually existing elements, and as such are useful fictions. There is an extended criticism of the alternative-possible-worlds approach championed by the American philosopher David Lewis. This major work will be read with interest by a wide range of philosophers.

Essence and causation are fundamental in metaphysics, but little is said about their relations. Some essential properties are of course causal, as it is essential to footprints to have been caused by feet. But I am interested less in causation's role in essence than the reverse: the bearing a thing's essence has on its causal powers. That essencemight make a causal contribution is hinted already by the counterfactual element in causation; and the hint is confirmed by the explanation essence offers (...) of something otherwise mysterious, namely, how events exactly alike in every ordinary respect, like the bolt'ssuddenly snapping and its snapping per se, manage to disagree in what they cause. Some prior difference must exist between these events to make their causal powers unlike. Paradoxically, though, it can only be in point of a property, suddenness, which both events possess in common. Only by postulating a difference in themanner — essential or accidental — of the property's possession is the paradox resolved. Next we need an account of causation in which essence plays an explicit determinative role. That account, based on the idea that causes should becommensurate with their effects, is thatx causesy only if nothing essentially poorer would have done, and nothing essentially richer was needed. (shrink)

This book aims at reconciling the emerging conceptions of mind and their contents that have, in recent years, come to seem irreconcilable. Post-Cartesian philosophers face the challenge of comprehending minds as natural objects possessing apparently non-natural powers of thought. The difficulty is to understand how our mental capacities, no less than our biological or chemical characteristics, might ultimately be products of our fundamental physical constituents, and to do so in a way that preserves the phenomena. Externalists argue that the significance (...) of thought turns on the circumstances of thinkers; reductionists hold that mental characteristics are physical; eliminationists contend that the concept of thought belongs to an outmoded folk theory of behavior. John Heil explores these topics and points the way to a naturalistic synthesis, one that accords the mental a place in the physical world alongside the non-mental. (shrink)