I say only that the study of the behaviour of living bodies, in the present state of our knowledge, is distinct from physics.
I believe an "unconscious" desire is merely a causal law of our behaviour,* namely, that we remain restlessly active until a certain state of affairs is realized, when we achieve temporary equilibrium If we know beforehand what this state of affairs is, our desire is conscious; if not, unconscious.
Something closely analogous to knowledge and desire, as regards its effects on behaviour, exists among animals, even where what we call "consciousness" is hard to believe in; something equally analogous exists in ourselves in cases where no trace of "consciousness" can be found.
No sooner did she perceive any symptom of love in his behaviour
to Elinor, than she considered their serious attachment as certain, and looked forward to their marriage as rapidly approaching.
Those behaviours are an attempt by the affected person to soothe anxiety, depression, and self-hatred which result from internal distress.
The operations of the brain result from a balance between inputs from heredity and environment -- nature and nurture -- and this balance should always be reflected in research into the biology of behaviour.