Mark Heller

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.

The best reason to believe in temporal parts is to avoid commitment to coincidence—roughly, two objects occupying exactly the same space at exactly the same time. Most anti-coincidence arguments for temporal parts are fission arguments. Gaining some notice, however, are vagueness arguments. One goal of this paper is to clarify the way a temporal-parts ontology avoids coincidence, and another is to clarify the vagueness argument, highlighting the fact that it too is an anti-coincidence argument. The temporal-parts alternative to coincidence has been challenged on the grounds that it leads to a kind of coincidence of its own. When something that is a temporal part of more than one person thinks about its future self, it must be thinking about a multitude of people. Thus, there must be many people thinking many thoughts in that region occupied by the thinking part. The third goal of this paper is debunking this attack on temporal parts.

In 1962 Hilary Putnam forced us to face the possibility of robot cats. More than twenty years later Daniel Dennett found himself doing battle with mad scientists and other “bogeymen.” Though these two examples are employed in different philosophical arena, there is an important connection between them that has not been emphasized. Separating the concept associated with a kind term from the extension of that term, as Putnam and others have urged, raises the possibility of accepting counterexamples to compatibilistic analyses without rejecting compatibilism. Even if no compatibilist analysis of our concept of free action is acceptable, a compatibilist account of the essential nature of free action may be.

The Donkey Problem (as I am calling it) concerns the relationship between more and less fundamental ontologies. I will claim that the moral to draw from the Donkey Problem is that the less fundamental objects are merely conventional. This conventionalism has consequences for the 3D/4D debate. Four-dimensionalism is motivated by a desire to avoid coinciding objects, but once we accept that the non-fundamental ontology is conventional there is no longer any reason to reject coincidence. I therefore encourage 4Dists to become even more radical—embrace the Donkey Problem’s conventionalism and deflate the debate between 3Dists and 4Dists.

René Descartes, one of the dominant figures in the history of philosophy, has been accused of one of the most obvious mistakes in the history of philosophy — the so-called cartesian circle. It is my goal in this paper to arrive at an understanding of Descartes's work that attributes to him a theory that should be of philosophical interest to contemporary epistemologists, is consistent with, and suggested by, the actual text, and avoids the circle.I begin with a brief explanation of the supposed circle. In his search for absolute certainty Descartes requires that in order for a proposition to be an instance of knowledge it must be indubitable for the knower, and in order for it to be indubitable for the knower she must be able to eliminate any possibility of the belief's being false. It is to provide a means to satisfy this requirement that Descartes proposes the principle whatever is clearly and distinctly perceived cannot be false.And it seems that Descartes's defense of CD traps him in the circle.

In 1962 Hilary Putnam forced us to face the possibility of robot cats. More than twenty years later Daniel Dennett found himself doing battle with mad scientists and other “bogeymen.” Though these two examples are employed in different philosophical arena, there is an important connection between them that has not been emphasized. Separating the concept associated with a kind term from the extension of that term, as Putnam and others have urged, raises the possibility of accepting counterexamples to compatibilistic analyses without rejecting compatibilism. Even if no compatibilist analysis of our concept of free action is acceptable, a compatibilist account of the essential nature of free action may be.