Further, we see that from the same property of human nature, whence it follows that men are merciful, it follows also that they are envious and ambitious.

Lastly, if we make appeal to Experience, we shall find that she entirely confirms what we have said; more especially if we turn our attention to the first years of our life.

We find that children, whose body is continually, as it were, in equilibrium, laugh or cry simply because they see others laughing or crying; moreover, they desire forthwith to imitate whatever they see others doing, and to possess themselves of whatever they conceive as delighting others: inasmuch as the images of things are, as we have said, modifications of the human body, or modes wherein the human body is affected and disposed by external causes to act in this or that manner.
PROP.XXXIII.

When we love a thing similar to ourselves we endeavour, as far as we can, to bring about that it should love us in return.
Proof .-- That which we love we endeavour, as far as we can, to conceive in preference to anything else (III.

xii.).