Imagination And The Senses

Imagination and the senses have a relationship that is not as simple as the latter providing the former with the entirety of its foundation, but it is also not as simple as the former preceding absolutely everything that the latter experiences.  Here, the focus is on the process of imagining material objects, not on imagination as it relates to purely abstract logical concepts, which material objects have no direct relevance to.  Rather, the matter at hand is to what extent sensory experiences play in providing imagination with an arsenal of concepts that can be assembled in one's mind.

It is not impossible to imagine an object that can be observed in the external world before one has actually seen it, just as it is not impossible to conceive of a logically possible object that may not even exist in the world of one's perceptions at all.  This is what allows some people to think of new objects they wish to create, objects that they might have no direct experience with.  In either case, the process may or may not literally involve mental imagery of the object or concept in question, but there is nothing inaccessible about the mere concepts of objects or creatures.

Of course, it is unlikely that many people would come to certain concepts of external objects apart from some kind of baseline sensory experience.  Reason and introspection do allow for plenty of reflection on their own, but it is not probable that one would think about the concept of an apple or a stone without the senses.  It is not that one must see something to imagine it; it is that there would be little to prompt such imaginings if one had seen nothing at all.  Information about the concepts of specific material items is still simply unlikely to surface in a vacuum.  While imagination does not totally depend on the senses, basic experiences with the latter shape the foundation from which the former is used. 

It is reason, however, not the senses, that ultimately dictates what imagination can and cannot do.  That logic can be wielded apart from the senses is what makes imagination possible even when the senses are not directly responsible for supplying it with concepts or imagery: logical truths can be easily grasped even in the total absence of sensory stimulation because they are immediately understood by the intellect, which is a component of consciousness and not something created by the senses.  This is why things can be imagined before they are seen for the first time and why that which is visible can inspire imaginings of that which seems to not be present in the external world.

Imagination, contrary to what many think, is as confined by the metaphysical existence of reason just as much as everything else (though the two are not opposed [1]), and the accessibility of reason independent of sensory experiences means that existing or nonexistent things alike could be imagined beforehand.  How else could someone think of a scenario they have never experienced?  How else could someone hypothesize the presence of a material entity they have not actually seen?  It is the a priori nature of reasoning that permits this--even if imagination often needs the senses to send it in a certain direction, one can always go beyond what the senses provide.

[1].  https://thechristianrationalist.blogspot.com/2018/08/reason-does-not-contradict-imagination.html