Thinking (dianoia) itself moves nothing, but only thinking for the sake of something and practical (praktike); for this is the governing source (arche) also of productive activity (poietike)…. Now, regarding the thing done (to prakton) acting-well is the end, and desire (or appetite; orexis) is for this. Therefore, choice (proairesis)- [the source of action] – is either appetitive intellect (orektikos nous) or thoughtful appetite (orexis dianoetike), and a human being (anthropos) is such a principle (or source; arche).
Aristotle – Nichomachean Ethics 6:2 1139a36-1139b7
As Aristotle noted long ago, thought – or speech or reason – itself moves nothing, especially, one can add, thought merely laid down next to appetite. Thought, to be effective, must be inseparable from appetite.
The true source of action is not abstract thought, nor even thought applied to some separate motor or motive force, but rather a concretion, a grown-togetherness, of appetite and mind, so intertwined that one cannot say for sure whether the human principle of action is a species of desire become thoughtful, or an activity of intellection suffused with appetite. How mind and desire become grown together is, of course, a great question, but it is rarely accomplished by applying purely rational doctrines or rules in a passionless way to human agents. On the contrary, the true beginning is rather with the direct but unreflective education of our loves and hates, our pleasure and pains, gained only in practice, through habituation and by means of praise and blame, reward and punishment. Anyone concerned with influencing conduct must be concerned with these in-between powers of the soul, themselves irrational (in the sense of nonreasoning) but fully amenable to reason (in the sense of being formed, to begin with, in accordance with the reasons of one’s parents, teachers and laws, and being open to further refinement through the exercise of one’s own powers of deliberation and discernment).
Leon R. Kass – Life, Liberty, and the Defense of Dignity: The Challenge for Bioethics p.68
I have been driven to regard as the earliest recognizable sexual organization the so-called “cannibalistic” or “oral” phase, during which the original attachment of sexual excitation to the nutritional instinct still dominates the scene. It is not to be expected that we should come upon direct manifestations of this phase, but only upon indications of it where disturbances have been set up. Impairment of the nutritional instinct (though this can of course have other causes) draws our attention to a failure on the part of the organism to master its sexual excitation. In this phase the sexual aim could only be cannibalism – eating… It is well known that there is a neurosis which occurs at a much later age, in girls at the time of puberty or soon afterwards, and which expresses aversion to sexuality by means of anorexia. This neurosis will have to be brought into relation with the oral phase of sexual life. The erotic aim of the oral organization further makes its appearance at the height of a lover’s paroxysm (in such phrases as “I could devour you with love”) and in affectionate intercourse with children, when the grown-up person is pretending to be a child himself… Permanent marks have been left by this oral phase of sexuality upon the usages of language. People commonly speak, for instance, of an “appetizing” love-object, and describes persons they are fond of as “sweet”… In dreams sweet things and sweetmeats stand regularly for caresses or sexual gratifications.
Sigmund Freud – Three Case Histories p.265