To understand more clearly: We say in the blessing of Yotzer:1 "He who in His goodness renews each day, continuously, the work of Creation." G-d recreates the world not only daily, but constantly. Note that the term used is that of renewal and creation, and not the progressive descent of ilah and olul.
Ilah and olul are comparable, and as such ilah is responsible for the emergence of olul. When the olul emerges, the ilah then invests itself in it and gives it vitality. Prior to its emergence as a distinct entity, the olul already exists within the ilah. Although while submerged in the ilah, the olul is on a radically different plane, it remains essentially the same; the difference is only in degree.
The ilah and olul of intellect and emotion as well as that of thought and speech offer two proofs that this is indeed so.
Regarding the ilah and olul of intellect and emotion, we observe that emotion is already found in the intellect. An individual, upon comprehending that a matter is good for him, will be filled with intellectual excitement and warmth. This excitement and warmth is emotion as it is contained in intellect.
However, the emotion of intellect is in no way similar to the emotional response of the heart. Emotion in intellect is merely an objective excitation. True emotion, emotion of the heart, is the deeply felt subjective ecstasy that the matter is good for him. The excitement resulting from the good accruing to an individual is radically different from the excitement that results from the contemplation of a subject's intrinsic goodness.
Though the emotional response of mind and heart are so dissimilar, both are of one emotional essence. Therefore heartfelt emotion will emerge from emotion of the intellect. Rather than being something new, heartfelt emotion is but a revelation of what was previously latent.
The same is true with the ilah and olul of thought and speech. A person says that which he has previously thought about. Without prior thought, speech is incoherent.
The progressive order of thought is as follows: A person first thinks of a pure concept, then words form in his mind in consonance with the subject matter. The words are then arranged in a form that can be verbalized.
Speech, then, is but a revelation of that which was previously concealed in thought, and is not something new.
In summary: G-d renews the world from moment to moment. Ilah and olul are comparable. Though the olul as it emerges as an independent entity is very different from what it was when contained in the ilah, its essence remains unchanged. This is observed both in emotion and intellect, as well as in speech and thought.