“Men enter into life solely desirous of seeking their own happiness. The whole edifice of virtue arises from the observed fact, that owing to the constitution of our nature, and the intimacy of our social relations, it is necessary for our happiness to abstain from some courses that would be immediately pleasurable and to pursue others that are immediately the reverse. Self-interest is the one ultimate reason for virtue, however much the moral chemistry of Hartley may disguise and transform it. Ought or ought not, means nothing more than the prospect of acquiring or of losing pleasure. The fact that one line of conduct promotes, and another impairs the happiness of others is, according to these moralists, no reason whatever for pursuing the former or avoiding the latter, unless such a course is that which brings us the greatest happiness. The happiness may arise from the action of society upon ourselves, or from our own naturally benevolent disposition, or, again, from an association of ideas, which means the force of a habit we have formed, but in any case our own happiness is the one possible or conceivable motive of action. If this be a true picture of human nature, the reasonable course for every man is to modify his disposition in such a manner that he may attain the greatest possible amount of enjoyment. If he has formed an association of ideas, or contracted a habit which inflicts more pain than it prevents, or prevents more pleasure than it affords, his reasonable course is to dissolve that association, to destroy that habit. This is what he 'ought' to do according to the only meaning that word can possess in the utilitarian vocabulary. If he does not, he will justly incur the charge of imprudence, which is the only charge utilitarianism can consistently bring against vice.”

“Chemistry and the Notion of the Feelings. Philosophical problems, in almost all their aspects, present themselves in the same interrogative formula now as they did two thousand years ago: how can a thing develop out of its antithesis, e.g. the reasonable from the non-reasonable, the "animate from the inanimate" ["sentient in the dead", Hollingdale (1986)], the logical from the illogical, altruism from egoism, disinterestedness from greed, truth from error? The metaphysical philosophy formerly steered itself clear of this difficulty to such extent as to repudiate the evolution of one thing from another and to assign a miraculous origin to what it deemed highest and best, due to the very nature and being of the "thing-in-itself." The historical philosophy, on the other hand, which can no longer be viewed apart from physical science, the youngest of all philosophical methods, discovered experimentally (and its results will probably always be the same) that there is no antithesis whatever, except in the usual exaggerations of popular or metaphysical comprehension, and that an error of the reason is at the bottom of such contradiction.

A visual of Friedrich Nietzsche on the need for a "chemistry of the moral", aka a science of moral chemistry. [1]

There is, strictly speaking, neither unselfish conduct, nor a wholly disinterested point of view. Both are simply sublimations in which the basic element seems almost evaporated and betrays its presence only to the keenest observation. All that we need and that could possibly be given us in the present state of development of the sciences, is a chemistry of the ‘moral’, ‘religious’, ‘aesthetic’ conceptions and ‘feeling’, as well as of those ‘emotions’ which we experience in the affairs, great and small, of society and civilization, and which we are sensible of even in solitude. But what if this chemistry established the fact that, even in its domain, the most magnificent results were attained with the basest and most despised ingredients? Would many feel disposed to continue such investigations? Mankind loves to put by the questions of its origin and beginning: must one not be almost inhuman in order to follow the opposite course?”

“A reflection in the Nachlass, written during the period that produced Daybreak, gives us an interesting indication of the links between intellectual chemistry and the chemical theory (in the proper sense) of living beings:

‘In the chemical world reigns the most vivid perception of the diversity of forces. But a protoplasm as a diversity of chemical forces, has only an imprecise and indeterminate overall perception of a foreign object.’

This fragmentation of me field of the real must be taken into account by a sort of ‘psycho-chemistry’, or, to take the term in its authentic generality, a ‘psycho-analysis’! A strange aphorism goes so far as to link moral activity to ‘the modification of the chemical constitution of me body’. Meanwhile, the ideational constitution seeks to transform the chemistry of representations. These forces are analogous to the corporeal forces which refract them. Passing over On the Genealogy of Morals, the chemical inspiration figures more explicitly in The Will to Power. On the other hand, chemistry demonstrates that ‘there is nothing which is not transformable.’ Chemistry studies the flux and transformation of the characteristics of substances, and it figures as a becoming-universe, the milieu proclaimed in Wille zur Macht (Will to Power). On the other hand, chemistry also figures as a type of order in becoming that which exceeds all legality, in which case it serves to explain the ‘relations of force’:

‘I am wary of speaking in terms of chemical laws: that leaves a moral aftertaste. It is rather a question of the absolute establishment of relations of force (Machtverhänissen or ‘power relations’).’

One may argue that, according to the very specifications of the Nietzschean project, a slippage occurs in the manner of conceiving the nature and the sense of this moral chemistry, to the extent that, increasingly, the atoms-representations become dynamized in forces, from a Boscovitchian perspective. But the important aspect remains, for our purposes, the persistence of the chemical reference, which serves to identify the analytical and dynamic project.”

See main: Human chemical thermodynamics