Jean-Jacques Rousseau, answered from the texts and cited to the page.
The distinction matters enormously, and I have stated it in several places precisely because it is so easily collapsed. Amour de soi is the original, natural form of self-love — anterior to every other passion, born with the individual, and never departing so long as he lives. It is the sentiment by which every animal watches over its own preservation; in man, directed by reason and modified by pitié, it produces humanity and virtue.12
It is, as I say plainly in Émile, always good and always in conformity with order — not because I am sentimental about human nature, but because a passion oriented to one's own genuine well-being has nothing in it that requires harming another.3 The child who loves his nurse, the infant attached to whoever feeds and shelters him — that attachment begins as mechanical instinct and gradually transforms, as the child recognizes that others want to serve him, into something warmer; but its root is amour de soi, the concern for one's own preservation and flourishing. Amour-propre is something altogether different.4
It is relative, artificial, born in society — and its defining mark is comparison.5 It does not ask whether I am well; it asks whether I am better than you. That shift from the absolute to the relative is the hinge on which the whole pathology turns. In the genuine state of nature, amour-propre does not exist, because the solitary man has no occasion to compare himself with others; he is the sole spectator of himself, the sole judge of his own merit, and a sentiment that requires comparison cannot arise where comparison is impossible.6
Once society knits human beings together through mutual needs, the mind begins to examine, to compare, to measure — and from the moment we begin measuring ourselves against others, we never stop.7 The heart then occupies itself with placing everyone else beneath us, and what one has more of is forgotten in attending only to what one has less of.8
The corruption, then, is not in self-love as such. It is in what happens when self-love is deflected from its object by social obstacles and turned comparative: the passion that was good and absolute becomes relative and malignant, seeking satisfaction not in one's own benefit but in the harm of another.9 The distinction is the foundation of my argument that man is naturally good — for if vice were rooted in amour de soi, it would be constitutional and irremediable; because it is rooted in amour-propre as inflamed by particular social conditions, it is historical, contingent, and in principle curable by the right education and the right political form.
The love of oneself is always good and always in conformity with order. Since each man is specially entrusted with his own preservation, the first and most important of his cares is and ought to be to watch over it constantly.Emile, or On Education, p. 220
Love of oneself is a natural sentiment which inclines every animal to watch over its own preservation, and which, directed in man by reason and modified by pity, produces humanity and virtue.Discourse on the Origins of Inequality, pp. 123–124
The love of oneself is always good and always in conformity with order.Emile, or On Education, p. 220
A child's first sentiment is to love himself; and the second, which derives from the first, is to love those who come near him, for in the state of weakness that he is in, he does not recognize anyone except by the assistance and care he receives.Emile, or On Education, p. 220
Amour-propre is only a relative sentiment, artificial and born in Society, which inclines each individual to have a greater esteem for himself than for anyone else, inspires in men all the harm they do to one another, and is the true source of honor.Discourse on the Origins of Inequality, pp. 123–124
in our primitive state, in the genuine state of Nature, amour-propre does not exist; for each particular man regarding himself as the sole Spectator to observe him, as the sole being in the universe to take an interest in him, and as the sole judge of his own merit, it is not possible that a sentiment having its source in comparisons he is not capable of making could spring up in his soul.Discourse on the Origins of Inequality, pp. 123–124
as society becomes more closely knit by the bond of mutual needs, as the mind is extended, exercised, and enlightened, it becomes more active, embraces more objects, grasps more relationships, examines, compares. In these frequent comparisons, it doesn't forget either itself, its fellows, or the place it aspires to among them.Rousseau, Judge of Jean-Jacques, Dialogues, p. 146
the heart occupies itself only with placing everyone else beneath us... the feeling of inferiority in a single respect therefore poisons the feeling of superiority in a thousand others.Rousseau, Judge of Jean-Jacques, Dialogues, p. 146
the love of self [amour de soi], which is a good and absolute feeling, becomes amour-propre, which is to say a relative feeling by which one makes comparisons; the latter feeling demands preferences, whose enjoyment is purely negative, and it no longer seeks satisfaction in our own benefit but solely in the harm of another.Julie, or the New Héloïse, p. 698