The soul cannot exist apart from the body as its actuality. Aristotle introduced mind in the third book of his treatise as that part of the soul which knows and thinks. He explained that the mind is potentially its object and it becomes actual when it thinks. The difference is that the object of thought is the form only without the matter. Consequently, this part of the soul, which is called intellect, is not in any act before it thinks. Therefore, it is improbable that it would be mixed with body and that it would have physical qualities or have a physical organ.
Aristotle enlightened us when he explained that the mind works through an intermediary – images or imagination; however, imagination is unlike any senses, it cannot be replaced. Since this soul cannot be substituted, it's significant is stressed in Aristotle's treatise, "Imagination, too, differs from sensation and from thought; but without sensation there can be no imagination, and without imagination there can be no belief." On the Soul, Book III, 427b14-16 Since intellect is the form of forms while sensation is the form of sensible, it is evident that no one would be able to learn or understand anything without sensation. One must also contemplate with one's imagination. Images fantasmata resemble the things perceived, without the matter.
Immaterial images are the perceptible objects of the intellect. Imagination is said to be the tool between sensible world and higher cognition. It can manipulate the forms which allows us to make things up, creating false images. Aristotle recognize this, "Imagination is none of those which are always true, such as knowledge or the intellect; for imagination may be also false. It remains, then, to see if.