One of Hume's most well-known works and a masterpiece of philosophy, A Treatise of Human Nature is indubitably worth taking the time to read.

Some theories of personal identity allow some variation in what it takes for a person to survive from context to context; and sometimes this is determined by the desires of person-stages or the practices of communities.This leads to problems for decision making in contexts where what is chosen will affect personal identity.‘Temporal Phase Pluralism’ solves such problems by allowing that there can be a plurality of persons constituted by a sequence of person stages. This illuminates difficult decision making problems when (...) persons have to choose between different life-altering choices. (shrink)

The topic of personal identity has prompted some of the liveliest and most interesting debates in recent philosophy. In a fascinating new contribution to the discussion, Peter Unger presents a psychologically aimed, but physically based, account of our identity over time. While supporting the account, he explains why many influential contemporary philosophers have underrated the importance of physical continuity to our survival, casting a new light on the work of Lewis, Nagel, Nozick, Parfit, Perry, Shoemaker, and others. Deriving from his (...) discussion of our identity itself, Unger produces a novel but commonsensical theory of the relations between identity and some of our deepest concerns. In a conservative but flexible spirit, he explores the implications of his theory for questions of value and of the good life. (shrink)

I hold a view I call “Personal Identity Quasi-Relativism,” PIQR for short.

Philosophers often talk as if what it takes for a person to persist through time were up to us, as individuals or as a linguistic community, to decide. In most ordinary situations it might be fully determinate whether someone has survived or perished: barring some unforeseen catastrophe, it is clear enough that you will still exist ten minutes from now, for example. But there is no shortage of actual and imaginary situations where it is not so clear whether one survives. (...) Here reasonable people may disagree. There are "fission" cases where each of one's cerebral hemispheres is transplanted into a different head; Star-Trek-style "teletransportation" stories; actual cases of brain damage so severe that one can never again regain consciousness, even though one's circulation, breathing, digestion, and other "animal" functions continue; and stories where one's brain cells are gradually removed and replaced by cells from someone else, to name only a few favorites. (shrink)

I think recent discussions of content and reference have not paid enough attention to the role of language as a convention-governed system of communication. With this as a background theme, I explain the role of A-intensions in elucidating one important notion of content and correlative notions of reference.

It is my view that one essential difference between persons and other creatures is to be found in the structure of a person's will. Besides wanting and choosing and being moved to do this or that, men may also want to have certain desires and motives. They are capable of wanting to be different, in their preferences and purposes, from what they are. Many animals appear to have the capacity for what I shall call "first-order desires" or "desires of the (...) first order," which are simply desires to do or not to do one thing or another. No animal other than man, however, appears to have the capacity for reflective self-evaluation that is manifested in the formation of second-order desires. (shrink)

This provocative book attempts to resolve traditional problems of identity over time. It seeks to answer such questions as 'How is it that an object can survive change?' and 'How much change can an object undergo without being destroyed'? To answer these questions Professor Heller presents a theory about the nature of physical objects and about the relationship between our language and the physical world. According to his theory, the only actually existing physical entities are what the author calls 'hunks', (...) four-dimensional objects extending across time and space. This is a major contribution to ontological debate and will be essential reading for all philosophers concerned with metaphysics. (shrink)

This essay deals with the question of the morality of abortion and infanticide. The fundamental ethical objection traditionally advanced against these practices rests on the contention that human fetuses and infants have a right to life, and it is this claim that is the primary focus of attention here. Consequently, the basic question to be discussed is what properties a thing must possess in order to have a serious right to life. The approach involves defending, then, a basic principle specifying (...) a condition living things must satisfy to have a serious right to life, and the answer given makes it unlikely that this condition is satisfied by human fetuses and infants, though this tentative conclusion could be altered by future scientific studies of the development of the human brain. As things stand at the moment, however, it seems unlikely that developing humans acquire the physical basis of the psychological capacities on which the right to continued existence rests, and therefore unless there are other substantial objections to abortion and infanticide that undercut the above line of thought, the conclusion is that such practices are not intrinsically wrong. (shrink)

Why is two-dimensional semantics important? One can think of it as the most recent act in a drama involving three of the central concepts of philosophy: meaning, reason, and modality. First, Kant linked reason and modality, by suggesting that what is necessary is knowable a priori, and vice versa. Second, Frege linked reason and meaning, by proposing an aspect of meaning (sense) that is constitutively tied to cognitive signi?cance. Third, Carnap linked meaning and modality, by proposing an aspect of meaning (...) (intension) that is constitutively tied to possibility and necessity. (shrink)