To my astonishment, I found that the great majority of the men of science to whom I first applied protested that mental imagery was unknown to them, and they looked on me as fanciful and fantastic in supposing that the words “mental imagery” really expressed what I believed everybody supposed them to mean.  They had no more notion of its true nature than a colour-blind man, who has not discerned his defect, has of the nature of colour.  They had a mental deficiency of which they were unaware, and naturally enough supposed that those who affirmed they possessed it, were romancing.  To illustrate their mental attitude it will be sufficient to quote a few lines from the letter of one of my correspondents, who writes:—­

“These questions presuppose assent to some sort of a proposition regarding the ‘mind’s eye,’ and the ‘images’ which it sees....  This points to some initial fallacy....  It is only by a figure of speech that I can describe my recollection of a scene as a ‘mental image’ which I can ‘see’ with my ‘mind’s eye.’ ...  I do not see it ... any more than a man sees the thousand lines of Sophocles which under due pressure he is ready to repeat.  The memory possesses it, etc.”

Much the same result followed inquiries made for me by a friend among members of the French Institute.

On the other hand, when I spoke to persons whom I met in general society, I found an entirely different disposition to prevail.  Many men and a yet larger number of women, and many boys and girls, declared that they habitually saw mental imagery, and that it was perfectly distinct to them and full of colour.  The more I pressed and cross-questioned them, professing myself to be incredulous, the more obvious was the truth of their first assertions.  They described their imagery in minute detail, and they spoke in a tone of surprise at my apparent hesitation in accepting what they said.  I felt that I myself should have spoken exactly as they did if I had been describing a scene that lay before my eyes, in broad daylight, to a blind man who persisted in doubting the reality of vision.  Reassured by this happier experience, I recommenced to inquire among scientific men, and soon found scattered instances of what I sought, though in by no means the same abundance as elsewhere.  I then circulated my questions more generally among my friends and through their hands, and obtained the replies that are the main subject of this and of the three next chapters.  They were from persons of both sexes, and of various ages, and in the end from occasional correspondents in nearly every civilised country.