The purpose of this thesis is to examine the concept of motive and to make clear just how this concept relates to explaining human behaviour. First however, it will be advisable to make a few preliminary remarks. It will be admitted right from the start that there is something quite unusual about the form of words "Abe’s motive for killing Sam was that he wanted Sam's money". In fact we seldom use the word “motive" in everyday discourse. It is more (...) usual to ask not "What was x's motive for doing that?” but "Why did X do that?", and more usual to reply not "X's motive was such and such" but "X did it because of such and such". (shrink)