...if we had no call to question the truth of scientific principles except in the interest of maintaining that of conflicting ethical principles, I think many would be inclined to drop the latter -- to treat moral distinctions as pointing to nothing real beyond modes of feeling and believing which arise under certain conditions in men's minds. There is, they might say, no knowledge of good and evil, right and wrong, because nothing that happens really is any of these. There is only a discoverable connexion of events really happening and producing consequences, with feelings of pain and pleasure and the use of certain words, including words such as 'approval' and 'disapproval', to signify these feelings and their connexion with what produces them. Not every one would be satisfied with this account; some, with the best consideration that they could give to the question, would say that this was not what they meant when they said of anything that it was good or evil, right or wrong, that men ought or ought not to do certain actions; that in so speaking they recognized something for which if an account of the real left no room, it could not be correct. But others would dissent, and that without self-contradiction.
If, however, the principles underlying the scientific account of what the world really is, and how what really happens in it is related to what passes in the minds of men, were as little consistent with maintaining the distinction of truth from error as with maintaining that of good from evil or of right from wrong, then however shattering to the sufficiency of this account may be the denial that these principles are altogether true, I see no alternative to denying it. For the scientific account, though not claiming to be good or right, claims to be true; and it cannot reasonably do this, and abolish the possibility of knowledge.
Yet surely it does abolish this possibility. In the extreme instance of a Behaviourist account of the mind, that seems obvious; for if thought is laryngeal motion, how should any one think more truly than the wind blows? All movements of bodies are equally necessary, but they cannot be discriminated as true and false. It seems as nonsensical to call a movement true a a flavour purple or sound avaricious. But what is obvious when thought is said to be a certain bodily movement seems equally to follow from its being the effect of one. Thought called knowledge and thought called error are both necessary results of states of brain. These states are necessary results of other bodily states. All the bodily states are equally real, and so are the different thoughts; but by what right can I hold that my thought is knowledge of what is real in bodies? For to hold so is but another thought, an effect of real bodily movements like the rest. An intelligence not determined by what falls within this bodily system to which belong the conditions producing our thoughts might, if it were capable of knowing both the events in that system and the thoughts of it which these determine, discover under what conditions bodily events within the system produce thoughts of it agreeing with what this extraneous intelligence knows it to be, and under what conditions not. But the thought determined by these conditions could not know what the extraneous intelligence knew without being itself also extraneous to the system within which, nevertheless, the conditions determining it are supposed to lie. These arguments, however, of mine, if the principles of scientific theory are to stand unchallenged, are themselves no more than happenings in a mind, results of bodily movements; that you or I think them sound, or think them unsound, is but another such happening; that we think them no more than another such happening is itself but yet another such. And it may be said of any ground on which we may attempt to stand as true, Labitur et labetur in omne volubilis aevum.
That the principles, then, on which rests the scientific theory of the world are absolutely true is not only inconsistent with ethical theory; it is inconsistent with there being knowledge, or even true opinion. And therefore with themselves; for they claim to be matter of knowledge, or at least of true opinion. Since that is so, we are not required to make our ethical theory consistent at all points with the scientific account of the world; if our ethical theory is to be true, it must not be built upon the principles of the scientific account, or require their unquestioned acceptance. And this result, if correct, is of importance, and illustrates the necessity to Ethics of a metaphysical foundation.
H. W. B. Joseph
Some Problems in Ethics