Chapter 3 Accounting for Commitments: A priori Knowledge, Ontology, and Logical Entailments 1 Michaelis Michael In giving an account of our cognitive nature, modern epistemology has focused, understandably, on the question of what it is to know something. There are other aspects of that nature, which are not settled by that focus. My focus here is not that perfectly respectable question but a further question: in taking on an explicit commitment, which may or may not be knowledge, what other commitments have I taken on? This further question is part and parcel of our understanding each other, and ourselves. It requires an account of what we are implicitly committed to by dint of our explicit commitments. Were such an account forthcoming, we would easily account for what one knows in knowing something, or again, what one comes to believe in believing something. One very popular answer to that issue is to focus on the entailments of our explicit commitments. I am broadly in favour of this approach but find that beyond that agreement in generality there is room enough for major disagreement. I shall approach the matter by outlining the views of Frank Jackson who represents a particular view I find mistaken. Jackson introduces what I call the 1 This paper derives from work I did while supervised by David Lewis. I benefited immensely from his advice. I also benefited from remarks made on the work by Frank Jackson at the time. More recently I have benefited from comments by Aislinn Batstone, Stephen Hetherington, and Ralph Kennedy. Aspects of Knowing: epistemological essays Edited by S. S. Hetherington Copyright © 2006 by Elsevier Ltd. All rights of reproduction in any form reserved. ISBN: 0-08-044979-4 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 20 1 2 3 4 5 6 7 8 9 30 1 2 3 4 5 6 7 8 9 40 Ch003.qxd 2/24/06 6:38 PM Page 35