Susanne Langer was one of the psychologist/philosophers my mother especially revered, mostly for her work on symbols and symbol-making in language. I used the indexes in 3 of her works to explore what she had to say about imagination, and extracted these quotable bits:
An object is not a datum, but a form construed by the sensitive and intelligent organ, a form which is at once an experienced individual thing and a symbol for the concept of it, for this sort of thing... Philosophy in a New Key 89...the fact is that our primary world of reality is a verbal one. Without words our imagination cannot retain distinct objects and their relations... 126
...In a naive stage of thought, facts are taken for granted; matters of fact are met in practical fashion as they become obvious. If it requires further facts to explain a given state, such further facts are simply assumed. Imagination supplies the, philosophical interest sanctions them, and the popular mind accepts them on quite other grounds than empirical evidence. This pre-scientific type of thought, systematic enough in its logical demonstrations, but unconcerned about any detailed agreement with sense-experience, has been described and commented upon as often as the history of philosophy has been written: how Plato ascribed circular orbits to the planets because of the excellence of circular motion, but Kepler plotted those orbits from observation... 269-270
...the power of symbols enables us not only to limit each other's actions, but to command them... The story of man's martyrdom is a sequel to the story of his intelligence, his power of symbolical envisagement., which puts on him a burden that purely alert, realistic creatures do not bear —the burden of understanding. He lives not only in a place, but in Space; not only at a time, but in History. So he must conceive a world and a law of the world, a pattern of life, and a way of meeting death. All these things he knows, and he has to make some adaptation to their reality. 286-287
The decisive function in the making of language comes, I think, from quite another quarter than the vocal-auditory complexes that serve its normal expression. That other quarter is the visual system, in which the visual image —the paradigm of what, therefore, we call "imagination"— almost certainly is produced. Philosophical Sketches 37
...this recognition of images as representations of visual things is the basis on which the whole public importance is built —their use for reference... that lability of imagination, an openness to influence... 43
...the tendency of imagers with traits in common to fuse and make a simplified image —that is, a schematic— and you see how much of our image making would become casual acts of ideation, without any specific memory bonds to perceptual experiences 44 [imagine a dragon...]
...the one [sic!] animal species that has developed speech: the power of elaborate vocalization, the discriminative ear that heard patterns of sounds, the nervous mechanisms that controlled utterance by hearing inner and outer sounds, and the tendency to utter long passages of sound in gatherings of many individuals —that is, the habit of joint ululation... 46
...it is the education of vision that we receive in seeing, hearing works of art —the development of the artist's eye [or ear], that assimilates ordinary sights (or sounds, motions, or events) to inward vision... Wherever art takes a motif from actuality —a flowering branch, a bit of landscape, a historic event, or a personal memory, any model or theme from life&mdasdh; it transforms it into a piece of imagination, and imbues its image with artistic vitality. The result is an impregnation of ordinary reality with the significance of created form. 88
...our mental talents have largely freed us from that built-in behavior called instinct. The scope of our imagination gives each of us a separate world, and a separate consciousness... 110
...the peculiar tendency of the human brain to use the sense impressions it receives not only as stimuli or obstacles to physical action, but as material for its specialized function, imagination 138
...we not only see things, but at the same time imagine them to have all sorts of properties that one cannot see. Animals respond to outside stimuli either overtly or not at all; but men respond largely in a cerebral, invisible way. producing images, notions, figments of all sorts that serve as symbols for ideas. The result is that we live in a web of ideas, a fabric of our own making wherein we catch the contributions of outside reality, sights, sounds, smells, and so on... 139
At the center of human experience, then, there is always the activity of imagining reality, conceiving the structure of it through words, images, or other symbols, and assimilating actual perceptions to it as they come —that is, interpreting them in the light of general, usually tacit, ideas. 141
The essence of human mentality is the use of images not as sheer memory traces, but as symbols thatn may be put together freely, elaborated, and treated as mental pictures of the most various experiences, the power of seeing one thing in another. 145
Quotes Jean Philippe:
Literally speaking, imagination is the activity which embodies in mentally perceptible forms the effects of our sensory impressions, present or past. Fashioned by this action, ... the image is neither a memory nor an invention; it is a sheer representation, and image in the elementary and primitive sense of the word. [It is the modulus of imagination:] ...In the complexity of our mental organization it is a sort of living cell, which maintains its life through manifold and diverse transformations.
Mind: An Essay On Human Feeling, vol 1: 93...works of art are not natural occurrences with the stamp of life upon them. They are constructed symbols, made in the mode of imagination, because imagination reflects the forms of feeling from which it springs, and the principles of representation by which human sensibility records itself. ...the endless, varied improvisations of ordinary life in which imagination is more or less constantly engaged. 99
...The only adequate symbolic projection of our insights into feeling... is artistic expression, and the material for this is furnished by the natural resources of imagination. But artistic expression has an enormous range; for what we usually call a mental image —a visual fantasy— is only one kind of figment produced by our brain, prodigally, in sleep as well as waking, apparently without effort. Forms of sound and of bodily movement and even envisagements of purposeful action are similarly engendered, and have the same sort of plasticity and the same tendency to take on symbolic functions as visual forms. With these diverse materials, variously endowed people create works of art in the several great orders —music, drama, painting, dance, and so on. The potentialities of the imaginative mode seem to be endless. 104
Imagination, I think, begins in this fashion: its lowest form is this organic process of finishing frustrated perceptions as dream figments... For eons of human (or proto-human) existence imagination probably was entirely involuntary, as dreaming generally is today, only somewhat controllable by active or passive behavior, in the one case staving it off, in the other inviting it.. But what finally emerged was the power of image-making... Mind: An Essay On Human Feeling, vol 2: 283
What we ordinarily think of as 'imagination' is a directed process, an entertainment of images and often verbalized concepts whereby we organize our practical knowledge and, especially, orient our emotional reactions to the ever-emergent situations which form the scaffold of life. 288