The primary goal of this thesis is to determine in what way moral considerations are related to motives and reasons for action. This relation can be characterized in one of two ways. One can adopt an internalist position, which holds that the conn ction between moral considerations and motives or reasons for action is necessary, or one can adopt an externalist position, which holds that this connection is purely contingent. This thesis will proceed primarily by means of examining and evaluating the arguments put forth by David O. Brink in favour of a very thoroughgoing version of externalism, and to a lesser degree by means of examining the views of Philippa Foot, another prominent externalist. While I am willing to admit that some of the stronger forms of internalism are unacceptable, I am not willing to accept the strong externalist claim that there is no necessary connection whatsoever between morality and rationality. (Abstract shortened by UMI.)