"There is no such thing as an age for love ... because the man capable of loving — in the complex and modern sense of love as a sort of ideal exaltation — never ceases to love. I will go further; he never ceases to love the same person. You know the experiment that a contemporary physiologist tried with a series of portraits to determine in what the indefinable resemblances called family likeness consisted? He took photographs of twenty persons of the same blood, then he photographed these photographs on the same plate, one over the other. In this way he discovered the common features which determined the type. Well, I am convinced that if we could try a similar experiment and photograph one upon another the pictures of the different women whom the same man has loved or thought he had loved in the course of his life we should discover that all these women resembled one another. The most inconsistent have cherished one and the same being through five or six or even twenty different embodiments."
January 1, 1970
https://en.wikiquote.org/wiki/Paul_Bourget