A

LETTER

TO

PROFESSOR STEWART,

ON THE

OBJECTS OF GENERAL TERMS,

AND ON THE

AXIOMATICAL LAWS OF VISION.

SECOND EDITION.

TO WHICH ARE HERE ADDED,

SOME REMARKS ON THE MONTHLY REVIEW ON THIS SUBJECT.

BY J. FEARN, ESQ.

London:

ΤΟ

DUGALD STEWART, ESQ.

F. R. SS. LOND. AND EDIN. &c. &c. &c.

FORMERLY PROFESSOR OF MORAL PHILOSOPHY IN THE

UNIVERSITY OF EDINBURGH.

SIR, In presenting a view of the two following subjects, each of which has occupied the attention and urged the genius of thinking men, to a great and celebrated extent, I am impelled by reasons of no ordinary complexion: And, while it is to be expected that the topic which stands first subjoined, may, in the outset, interest a more numerous class of literary persons, I am highly urged to solicit the important issue of your earnest notice of that one which is placed LAST. The former subject, however, besides its own importance, has a certain bearing upon the latter, although it be not obvious here.

The matter of the " LAWS OF VISION," to which I here attach the greater interest, is presented as exhibiting what I (who certainly speak under strong inducements to caution) am obliged, by the nature of the thing, to consider a mathematical analysis of the constituents, or cause, of VISIBLE FIGURE. This, I apprehend, it must be considered; since the FOUR LAWS OF VISION are not physical laws merely, but are also FOUR AXIOMS, whose truth consequently is necessary, and whose NATURE is certainly mathematical. Fully anticipating, as I do, the first impression of so extraordinary a matter, and sensible of the utility of some sort of passport, in my peculiar case; may I therefore be permitted to offer the following observations?

When, about two years since, I ventured to publish a few copies of the "Principles of Primary Vision," (the first hint concerning which, appeared about four years back) I had indeed a confident hope that I should have to repeat the subject: but I did not expect

so curious and valuable a support, as the discovery that I am completely borne out by the rigorous assumption of an illustrious Greek Geometer, Such, however, is an authority which, owing to a recent communication, I am enabled to cite, and therefore purpose to bring forward here; not, however, without the additional concurrence of living individuals; which, together, form a very different voucher from my own very questionable judgment, as to whether this matter is what I conceive it to be.

Valuing, as I must do, the concurrent authority of PROCLUS, thus made known to me; I rest no undue confidence either upon his, or upon any other single voice. In the present case, indeed, the imperative nature of the evidence looks down upon single suffrage: but, since even mathematical propositions must bow to collective suffrage, I derive no small resolve from being able to pledge myself here, that among the acute and scientific individuals to whom the matter has been personally communicated, there has occurred but one dissent, (limited to inessentials) and that one has not survived discussion. The principal value, therefore, which I attach to the concurrence of PROCLUS is, that I feel no reluctance in making an open use of it, for the advancement of the subject.

While I am naming that Geometer, it may be of material consequence to state, that although the fact assumed by him attests the truth of the Laws of Vision, yet these Laws have no dependance whatever on that fact. But of this I must speak hereafter. May I however add, that Proclus has not handed down his proofs; but that the fact itself was fallen upon by me, I need not say, without any knowledge that another had gone before. Indeed, that this fact, known to Proclus, was completely LOST to the moderns, AS TO ANY UTILITY, is fully manifest from its not being noticed by any one of those who have engaged on the great problem, to find the NATURE and PLACE of visible figure.

Of authorities, ancient and modern, who have ASSERTED the dominion of SENSE over the ELEMENTARY objects of GEOMETRY, there is a numerous host; and these are of the highest estimation: only they have all failed to prove their assumption by showing the PRECISE MANNER, HOW the elements of visible figure are either connected, or formed. PROCLUS alone (seconded by Barrow), is partly an exception, in having noted one included or subordinate fact; which, however, never led him to the FOUR AXIOMS OF VISION, nor to the PLACE of perceived figure.

Such, Sir, is the prospect of this matter: while, either from the

Since this was first printed, I have found the matter is further backed by a slight but unequivocal allusion of DR. BARROW, fully recognising the same fact that is assumed by PROCLUS: although neither of these writers deduce from it any consequences in philosophy.

want of some such passport as the foregoing, or from my own culpable remissness in not caring to urge the matter through the ordinary channels, or from some other cause, I am obliged to believe it cannot have reached your eye, or undergone the sentence of your judgment. Unquestionably I am bound to my contemporaries and to the future race, to place this matter in the direct channel of your notice, since the command to do so has fallen thus imperatively upon me.

Beside the AXIOMS OF VISION, themselves, let me now beg to suggest to notice, their very remarkable agreement with that astonishing metaphysical tenet of the HINDOOS, which makes “the whole of creation rather an energy than a work, by which the infinite mind, who is present at all times, and in all places, exhibits to his creatures a set of perceptions, like a wonderful picture, or piece of music, always varied, yet always uniform."

Upon the bare mention of this (I had almost said, divine) HINDOO TENET, it appears to me unavoidable to remark, that, if it can strictly be said that it "took its rise from a high theological speculation," it must have been indeed A HIGH one; since the most luminous results of modern physical research have but led, by a slow and groping_progress, toward this solar light of HINDOO PHILOSOPHY. Can any person without astonishment contemplate such a coincidence of results, meeting from so very distant sources, and flowing through such different channels?

The mind is rapt and lost in attempting to conjecture at what time, under what circumstances, and by what guidance, the early generations of our species were enabled to perfect a philosophy of such a flight, that the living spectator, of the highest cast, must feel shrunk in his intellectual dimensions on the comparison,-a. philosophy which teaches the moderns, at once to appreciate the genius of a BERKELEY, and to stop at the line where that genius overstept upon error,-which denies the INERTNESS of matter, without admitting such a CHIMERA as the NON-REALITY OF EXTENSION.-Such is the EXTERNAL WORLD of Hindoo Science: And, (so far, therefore, as any extrinsic coincidence can corroborate the sentence of internal reasoning,) may I not set value upon the fact, that this EXTERNAL WORLD OF THE HINDOOS, is to COLOR AND FIGURE in us, as we suppose EXTERNAL FIRE to be to the FIRE in a BODY which it heats? I indeed suppose this simile is vague; but I nevertheless affirm, that the relation appears to be as requisite and as close, in the former case as in the latter, after we have gone through the following analysis of the primary phenomena of vision.

The seeming correlation of these two subjects, namely, the HINDOO EXTERNAL WORLD, and what I have felt obliged to call the " AXIOMATICAL LAWS OF VISION," is the more satisfactory,