The following exchange is from Ch. 16 of THE WOODLANDERS by Thomas Hardy:
“You seem to be mightily in love with her, sir,” [Winterborne] said . . .
“Oh no—I am not that, Winterborne; people living insulated, as I do by the solitude of this place, get charged with emotive fluid like a Leyden jar with electric, for want of some conductor at hand to disperse it. Human love is a subjective thing—the essence itself of man, as that great thinker Spinoza the philosopher says—ipsa hominis essentia—it is joy accompanied by an idea which we project against any suitable object in the line of our vision, just as the rainbow iris is projected against an oak, ash, or elm tree indifferently. So that if any other young lady had appeared instead of the one who did appear, I should have felt just the same interest in her, and have quoted precisely the same lines from Shelley about her as about this one I saw. Such miserable creatures of circumstance are we all!”
“Well, it is what we call call being in love down in these parts, whether or no,” said Winterborne.
“You are right enough if you admit that I am in love with something in my own head, and no thing in itself outside it at all.”