The theories of most writers on Ethics, with whose works I am acquainted, appear to be based upon the assumption of the unique character of goodness or The Good. By the word unique these writers mean, I think, among other things that goodness cannot be analysed into or described in terms of anything other than itself, that it can be and is desired for its own sake and not for the sake of some other thing which is not goodness, and that the apprehension of or desire for goodness is a distinct and specific character of our mental states. By asserting, however, that the state of mind constituted by the apprehension of goodness, or that the state of emotion aroused by the desire for goodness, is distinguished by a specific and unique property, they do not, I think, necessarily mean that this property is the same as the specific property of goodness itself. Most writers on Ethics have also believed that man is free to desire goodness, and to act in accordance with his desire, that is to say, they have held in some form or other the doctrine of free-will.