From the above we conclude that intellect affects emotion in two ways: it affects the feeling itself and it affects the action which results from the feeling.
The feeling and the resultant action differ in that the olul [the actual feeling] is fashioned from the ilah [the intellect itself], while the magnitude of the feeling and the resultant action depend on the degree of illumination and vitality emanating from the intellect.
Yet only a glimmering of intellect is enclothed within the essential and practical levels of emotion, since intellect itself is but a glimmer relative to an individual's totality, and not his essence.
The brain performs many varied tasks, among them the transmission of knowledge and the creation of children. Both tasks relate to another individual. Although both come from the brain, there is a great difference in how they come about. Knowledge is transmitted through speech, while children are created in another manner. The transmission of knowledge is called "the transmission of a glimmer," while the creation of children is termed "the transmission of essence."
The difference in transmission is twofold: Knowledge is imparted in a spiritual manner, while the "transmission of essence" is done physically. Also, "the transmission of essence" is continued from generation to generation (for which reason the Jewish people are called, "Children of Avraham, Yitzchok and Yaakov"), while intellect may not be transmitted even from one generation to the next. Even when it is, such transmission is but "a glimmer of a glimmer," for intellect itself is but a glimmer.
Yet that intellectual glimmer is the vitalizing force of all emotion. For this reason, when, with the passage of time, the understanding that illuminates an emotion is dimmed whether it be the magnitude of a favor done by one's friend or the evil done by one's foe the emotion itself will wither, giving rise to the expression "ancient friends" or "ancient enemies." Clearly, the intellect permeating the emotion is the source of its vitality.
In summary: Intellect affects both the creation and the force of an emotion. However, intellect which enclothes itself in emotion is but a glimmer and is therefore deemed to be an "external transmission," in contrast to the transmission which comes from the brain in order to create a child, which is a transmission of essence.