Ethics, in the sense in which that word is used by philosophers, may be described as the theoretical treatment of moral phenomena. I use the phrase “moral phenomena” to cover all those facts and only those in describing which we have to use such words as “ought,” “right and wrong,” “good and evil,” or any others which are merely verbal translations of these.

In some sense every man has a moral right, or more properly a moral claim, to equality with other men. In what sense will, I hope, become apparent in the course of this paper. That there is such a claim in some sense is clear enough. “Equality before the law,” for example, is something which we all recognize to be right.

I much appreciate the honour of being invited to deliver the first Manson lecture, which, its founder has laid down, is to be devoted to the consideration of some subject of common interest to philosophy and medicine. I cannot think of anything which better fulfils that condition than the neurological approach to the problem of perception. The neurologist holds the bridge between body and mind. Every day he meets with examples of disordered perception and he learns from observing the effects of lesions produced by disease, or by the physiologist's experiments, something of how the neural basis of perception is organized. It is possible to study perception as though this was largely irrelevant. How far that view is right will be for you to judge when I have finished.

Poetry has to do with reality in its most individual aspect. It is thus at the opposite pole to science, and out of its reach. Studies like The Road to Xanadu, highly valuable though they may be in one way, do not help us in any measure to understand what poetry in itself is; nor do they heighten substantially our appreciation of poetry. This may seem rather obvious, but it is not in fact idle to say it. For our thought is apt to be unduly coloured to-day by the progress of science, and some of the votaries of science are prone to regard it, in the Biblical phrase, as ‘profitable unto all things.’ These are less naïve to-day than their prototypes a century ago, and they have a subtler psychology at their disposal when they turn to art. But their view is no less pernicious for that reason. Science has very certain limits, and we only bring it into contempt by forcing upon it a forlorn and unnatural enterprise beyond its own terrain. Some scientists, and they include eminent persons like Julian Huxley, have made that mistake in regard to our ideas of right and wrong, and have endeavoured to develop a science of ethics. It is not to the purpose here to expose the confusions involved in this particular act of aggression on the part of science. Science has nothing to do, in the final analysis, with our ideas of right and wrong. And it is also true, quite apart from ultimate questions about the meaning of value, that we cannot give a scientific analysis of art. Science may indeed help us to understand matters incidental to the pursuit of artistic activities.