If we ask the most fashionable sort of psychologist what love is, he says that it is the impulse urging us towards that end which is the fulfilment of any series of deeds or "behaviour-cycle"; the psychic thread, on which all the apparently separate actions making up that cycle are strung and united.

In this sense love need not be fully conscious, reach the level of feeling; but it _must_ be an imperative, inward urge.

And if we ask those who have known and taught the life of the Spirit, they too say that love is a passionate tendency, an inward vital urge of the soul towards its Source;[133] which impels every living thing to pursue the most profound trend of its being, reaches consciousness in the form of self-giving and of desire, and its only satisfying goal in God.

Love is for them much more than its emotional manifestations.

It is "the ultimate cause of the true activities of all active things"-- no less.
This definition, which I take as a matter of fact from St.Thomas Aquinas,[134] would be agreeable to the most modern psychologist; he might give the hidden steersman of the psyche in its perpetual movement towards novelty a less beautiful and significant name.