A psychology of the mind is impossible. All we find in the mind is a bundle of perceptions constantly shifting; having neither the consistancy nor universality requisite of a science. What is possible though, is a psychology of the mind’s affections.
Deleuze tells us that to found this new science of the mind’s affections Hume must first be a moralist and sociologist. Why is this the case? As Hume states the two forms by which the mind is affected are the passional and social. These two ensure the unity of this science because they imply each other.
It is here that Deleuze introduces a line of reasoning the meaning of which has escaped me:
“On the one hand, society demands and expects from each one of its members the display of constant reactions, the presence of passions able to provide motives and ends, and the availability of collective or individual characters: ‘A prince, who imposes a tax upon his subjects, expects their compliance’” (E&S, 21)
Investigating the Hume quote that Deleuze is citing will make things more clear.
“The same kind of reasoning runs through politics, war, commerce, economy, and indeed mixes itself so entirely in human life, that it is impossible to act or subsist a moment without having recourse to it. A prince, who imposes a tax upon his subjects, expects their compliance. A general, who conducts an army, makes account of a certain degree of courage. A merchant looks for fidelity and skill in his factor or super-cargo. A man, who gives orders for his dinner, doubts not of the obedience of his servants.” (Treatise, 405)
In all of these events, politics, war, commerce, and economy the presence of both the passions and social affects are present. A general conducting a war expect the passion of courage from his soldiers. He expects this courage to meet the ends that a war requires. In all of Hume’s examples, the person in charge demands a quality necessary to meet the end of whatever goal the person has. These people have at their disposal individuals to meet their demands. The social (politics, war, commerce, etc.) must be unified with the passions (compliance, courage, fidelity, etc.).
These examples may seem extreme but take an experience that every person can relate to, gaining employment. The social forces us to have a job or face starvation. To gain employment we must present ourselves with the passions necessary to meet the ends of the employer (compliance and fidelity). To anyone who has applied for a retail job, this is obvious. What are the absurd personality tests if not a chance to show your passion (authentic or otherwise) to gain employment? The social demands we are employed and the employers force a constant reaction, that being our compliance and fidelity.
Deleuze continues, “On the other hand, the passions implicate society as the oblique means for their satisfaction.” (E&S, 21)
While society demands constant reactions (the compliance to pay a new tax) it at the same time provides the means of satisfying the passions of the compliant taxpayer. In the case of the aforementioned job seeker, society demands they gain employment but at the same time provides the oblique means of satisfying their passions (in this case the money to satisfy said passions).
Now, so far as history is the study of “the relations between motive and action” (E&S 22) it follows the same patterns of the human passions. This is what Deleuze means when he says that one must first be a moralist, sociologist, and historian before being a psychologist. Let us remember that the only psychology is one of the mind’s affects. In other words, the mind is essentially a process of perceptions that happen to it. Or, in Deleuze’s phrasing “By itself and in itself, the mind is not nature, it is not the object of science” (E&S 22).
Now we come to the crux of the question of the first chapter: “…how does the mind become human nature?” (E&S 22).
So far we have seen passional and social affections as constituents of human nature, but these are not the only ones. The understanding and the association of ideas also play a part. The understanding plays the role of making our passions sociable and interests social. In other words, the understanding is necessary to attain our desires. As Deleuze puts it “By itself, though, the understanding is only the process of the passions on their way to socialization” (E&S 22).