[Editor’s Note: The following piece was published anonymously in the Edinburgh Review, Jan 1803, pp. 450-56. The author, Henry Brougham (1778-1868), was a barrister who later became Lord Chancellor of England. Brougham was an ardent advocate of the corpuscular theory of light. He savagely attacks Young’s wave theory and Young himself, not least because he sees the hypothesis of ether as inadmissable on the methodological grounds laid out by Newton.

This transcription retains Brougham’s spelling, punctuation and capitalization. Interpolations and translations in square brackets are mine, with one exception: the page reference to a previous article appears as a footnote on p. 454.

My thanks to Bethel McGrew who assisted me in the preparation of this electronic text. TJM]

ART. XVI. The Bakerian Lecture on the Theory of Light and Colours. By Thomas Young, M.D. F.R.S. Professor of Natural Philosophy of the Royal Institution. From Philosophical Transactions for 1802. Part I.

As this paper contains nothing which deserves the name, either of experiment or discovery, and as it is in fact destitute of every species of merit, we should have allowed it to pass among the multitude of those articles which must always find admittance into the collections of a Society which is pledged to published two or three volumes every year. The dignities of the author, and the title of Bakerian Lecture, which is prefixed to these lucubrations, should not have saved them from a place in the ignoble crowd. But we have of late observed in the physical world, a most unaccountable predilection for vague hypothesis daily gaining ground; and we are mortified to see, that the Royal Society, forgetful of those improvements in science to which it owes its origin, and neglecting the precepts of its most illustrious members, is now, by the publication of such papers, giving the countenance of its high authority to dangerous relaxations in the principles of physical logic. We wish to raise our feeble voice against innovations, that can have no other effect than to check the progress of science, and renew all those wild phantoms of the imagination which Bacon and Newton put to flight from her temple. We wish to recal philosophers to the strict and severe methods of investigation pointed out by the transcendent talents of those illustrious men, and consecrated by their astonishing success; and, for this purpose, we take the first opportunity that has been presented to us, of calling our readers’ attention to this mode of philosophizing, which seems, by the title of the paper now before us, to have been honoured with more than the ordinary approbation of the Council.

The author of this paper introduced himself to the literary world, by a few desultory remarks upon a theory, which he appeared to think new, but which had been previously exposed and refuted – the muscularity of the chrystalline lens. Soon after this, he retracted his opinion; and a year or two ago he again brought it forward. We do not know whether or not he has once more abandoned it; but we seriously recommend to him a due reflection upon the fact in the history of his opinions, which we have just now stated. Let it teach him a becoming caution in the publication of his theories. A discovery in mathematics, or a successful induction of facts, when once completed, cannot be too soon given to the world. But as an hypothesis is a work of fancy, useless in science, and fit only for the amusement of a vacant hour; as its excellence depends upon its simplification and agreement with every fact that can occur; as it requires continual polishing, touching, and retouching, in order to adapt it to the phenomena, the inventor comes precisely under that description of persons to whom the Roman satirist uttered those memorable injunctions, ‘Saepe vertas stylum’ — and ‘Nonum prematur in annum.’ [“May you often turn the stylus (to make corrections)”; “Let it (your first draft) be held back for nine years.”] To justify the apparent severity of these strictures, we quote, in the author’s own words, a few specimens of his vibratory and undulatory mode of reasoning.

In the present paper, page 43, we meet with the following sentence:

‘I am sorry to be obliged to recal, here, the assent which I was induced to give, at first sight, to a late author.’ Vide Phil Trans. for 1800, p. 28.

And in another paper of Dr Young in this very volume, we meet with the following passage, page 393.

‘The colours of mixed plates suggested to me an idea, which, it appears, leads to an explanation of the dispersion of colours by refractions, more simple and satisfactory than that which I advanced in the last Bakerian lecture.’

And again, in page 395, there is another correction or modification, as our author is pleased to call it, of another supposition in the same paper. It is difficult to argue with an author whose mind is filled with a medium of so fickle and vibratory a nature. Were we to take the trouble of refuting him, he might tell us, ‘My opinion is changed, and I have abandoned that hypothesis; but here is another for you.’ We demand, if the world of science, which Newton once illuminated, is to be as changeable in its modes, as the world of taste, which is directed by the nod of a silly woman, or a pampered fop? Has the Royal Society degraded its publications into bulletins of news and fashionable theories for the ladies who attend the Royal Institution? Proh pudor! Let the Professor continue to amuse his audience with an endless variety of such harmless trifles; but, in the name of Science, let them not find admittance into that venerable repository which contains the works of Newton, and Boyle, and Cavendish, and Maskelyne, and Herschell.

These remarks lead us to observe, that perpetual fluctuation and change of ground is the common lot of theorists. An hypothesis which is assumed from a fanciful analogy, or adapted from its apparent capacity of explaining certain appearances, must always be varied as new facts occur, and must be kept alive by a repetition of the same process of touching and retouching, of successive accommodation and adaptation, to which it originally owed its puny and contemptible existence. But the making of an hypothesis is not the discovery of a truth. It is a mere sporting with the subject; it is a sham-fight, which may amuse in the moment of idleness and relaxation, but will neither gain victories over prejudice and error, nor extend the empire of Science. A mere theory is in truth destitute of all pretensions to merit of every kind, except that of a warm and misguided imagination. It demonstrates neither patience of investigation, nor rich resources of skill, nor vigorous habits of attention, nor powers of abstracting and comparing, nor extensive acquaintance with nature. It is the unmanly and unfruitful pleasure of a boyish and prurient imagination, or the gratification of a corrupted and depraved appetite.

If, however, we condescend to amuse ourselves in this manner, we have a right to demand, that the entertainment shall at least be of the right sort – that the hypothesis shall be so consistent with itself, and so applicable to the facts, as not to require perpetual mending and patching – that the child which we stoop to play with shall be tolerably healthy, and not of the puny, sickly nature of Dr Young’s productions, which have scarcely stamina to subsist until their fruitful parent has furnished us with a new litter; to make way for which, he knocks on the head, or more barbarously exposes the first.

Our readers are well acquainted with the name of Euler. They probably know also how inadequate his success as a natural philosopher was to sustain the high fame which his mathematical achievements had gained to him. His optical hypothesis of vibration has been universally rejected, since the moment it was first published. But, in an evil hour, it fell in Dr Young’s way, some time during the year 1800; and, that it did not light in a barren place, we are entitled to conclude, from the Doctor having already produced no less than three huge papers upon it. The object of the one now before us, as well as the author’s notions of philosophising, may be conveniently gathered from the following passage.

‘The object of the present dissertation is not so much to propose any opinions which are absolutely new, as to refer some theories, which have been already advanced, to their original inventors, to support them by additional evidence, and to apply them to a great number of diversified facts, which have hitherto been buried in obscurity. Nor is it absolutely necessary, in this instance, to produce a single new experiment; for of experiments there is already an ample store, which are so much the more unexceptionable, as they must have been conducted without the least partiality for the system by which they will be explained. Yet some facts, hitherto unobserved, will be brought forward, in order to show the perfect agreement of that system with the multifarious phenomena of nature.’

We read this passage without much emotion, unless perhaps we might be inclined to pity the misguided pursuits of an ingenious man, who seems to have systematised into a sort of theory the method of wasting time. The following passage, however, excited somewhat of a livelier interest.

‘A more extensive examination of Newton’s various writings has shown me, that he was in reality the first that suggested such a theory as I shall endeavour to maintain; but his own opinions varied less from his theory, than is almost universally supposed: and that a variety of arguments have been advanced, as if to confute him, which may be found, nearly in a similar form, in his own Works, and this by no less a mathematician than Leonard Euler, whose system of light, as far as it is worthy of notice, was either, or might have been, wholly borrowed from Newton, Hooke, Huygens, and Malebranche.’

Those who are attached, as all may be with the greatest justice, to every doctrine which is stamped with Newtonian approbation, will probably be disposed to bestow on these considerations so much the more of their attention, as they appear to coincide more nearly with Newton’s own opinions. [Editor’s Note: this paragraph is part of the quotation from Young but is printed as if it were in Brougham’s words.]

A little farther acquaintance, however, with the Doctor’s paper has convinced us, that he is as little scrupulous in his quotations, as in his theories; that he delights as much to twit an authority, as to torture a fact; and, according to his usual vibratory method, after a second examination of the Newtonian writings, has changed the opinion which his first perusal gave him of their signification: a still farther examination of those difficult and sublime speculations of a real philosopher, will make the Doctor acquainted with the nature of his theory, and induce him to abandon the Eulerian hypothesis, if he continues to admit it on the supposition of its being stamped with Newton’s authority. Whilst we state this, we are very far from meaning to admit the criterion of authority appealed to by our author. We hold the highest authority to be of no weight whatever in the court of Reason; and we view the attempted to shelter this puny theory under the sanction of great names, as a desperate effort in its defense, and a most unwarrantable appeal to popular prejudice. But nothing can be more manifest, than that Dr Young grossly mistakes the opinion of sir Isaac Newton, in order to obtain the apparent sanction of his authority for his theory. In what light that modest and cautious philosopher viewed the hypothesis of an ether, we have had an opportunity of shewing in our last Number.* [p. 163] It is evident from his own words, which we have there quoted, that the existence of this medium is only stated by him as a vague hypothesis, which deserved no credit, unless for its applicability to a few facts. If the most elaborate theory had been detailed by Newton upon this subject, still, it would have become Dr Young to have considered, whether Newton ranked it among his propositions or his queries; whether he placed it among those things which he gave as proof, or amongst the hints which he threw out for farther investigation. Now, it will be observed, that almost all the quotations made by Dr Young are from the Queries subjoined to the 3d Book of the Optics; a few only are taken from his earlier papers in the Philosophical Transactions; none are to be found in the Principia; and the only mention of such a thing, which we meet with in the Optics, is accompanied with an express caution against believing that this is given as any thing but a mere hypothesis, intended to assist the imagination of those who, as Newton observes, can conceive nothing without such suppositions.

Let us attend to the concluding words of the Principa, where, talking of this hypothesis, he says, ‘Neque adest sufficiens copia experimentorum, quibus leges actionum bujus spiritus accurat determinari et demonstrari debent.’ [Nor are we furnished with that sufficiency of experiments which is required to an accurate determination and demonstration of the laws by which this electric and elastic Spirit operates.] Lib. 3. Schol. Gen. In the same memorable passage he tells us, hypotheses non fingo; seu metaphysicae, seu physicae, seu qualitatum occultarum, seu mechanicae in philosophia experimentali, locum non habent. [I do not feign hypotheses; ... [hypotheses,] whether metaphysical or physical, whether of occult or of mechanical qualities, have no place in experimental philosophy.] And in the introduction to the Queries in the third book of the Optics, he tells us, that he leaves them as materials for further search to others. It is scarcely possible to conceive a wider difference than that which subsists between the philosophy of Newton and the philosophy of Dr Young. While the former utterly rejects hypotheses, and asserts that our stock of facts upon the subject of the ether is insufficient; the latter says, that we have enow of experiments, and that we require only to have a stock of hypotheses. Newton proposes queries for the investigation of his successors. Dr Young claims the inheritance, and vainly imagines that he fulfils this destination, by ringing changes on these hypotheses, arguing from them as if they were experiments or demonstrations, twisting them into a partial coincidence with the clumsy imaginations of his own brain, and pompously parading, what Newton left as hints, in a series of propositions, with all the affectation of system. After all, it may be said, Newton amused himself with hypotheses, and so may Dr Young. Admitting that the Doctor’s relaxations were the same with his predecessor’s it must be remembered that the queries of Newton were given to the world at the close of the most brilliant career of solid discovery, that any mortal was ever permitted to run. The sports in which such a veteran might well be allowed to relax his mind, are mere idleness in the raw soldier who has never fleshed his sword; and though the world would gaze with interest upon every such occupation in the former, they would turn with disgust from the forward and idle attempts of the latter to obtrude upon them his awkward gambols.

We shall add but one remark upon the absurdity of supposing that the idea of an ether, thrown out at random by Sir Isaac Newton, has the smallest affinity with the clumsy theory of Euler, and of his commentator Dr Young. After demonstrating the properties of the rays of light considered as hard and minute bodies, in order to explain the theory of vision, and the colours of thick and thin plates, or to shew how the law of the fits discovered by induction, might be fancifully resolved into a still more general law without any induction – he amuses himself by conjecturing how the rays of light would act upon, and be affected by, an etherial, subtile medium, were the existence of such a fluid ascertained. That the concession of such an existence would enable us to resolve a variety of facts, apparently anomalous, into one general, and uniform, and sufficiently simple law, no one can entertain any doubt, who has read the passages in which this fanciful supposition is pursued by that great genius – great even in his most playful relaxations. But the clumsy hypothesis of Euler and Dr Young is, that the ether itself constitutes light; and their object is to twist the facts into some sort of agreement with what they conceive might be the laws of this fluid. From such a dull invention, nothing can be expected. It only removes all the difficulties under which the theory of light laboured, to the theory of this new medium, which assumes its place. It is a change of name; it teaches no truth, reconciles no contradictions, arranges no anomalous facts, suggests no ne experiments, and leads to [no(?)] new inquiries. It has not even the pitiful merit of affording an agreeable play to the fancy. It is infinitely more useless, and less ingenious, than the Indian theory of the Elephant and Tortoise. It may be ranked in the same class with that stupid invention of metaphysical theology, which, in order to account for the existence of evil, supposed the independent existence of an evil spirit; or that other notable contrivance, which, to explain the power of the Deity over matter, ingeniously supposed that all matter was the Deity.

Having, in general, stated our opinion of the merit which the theory may be allowed to possess, and endeavoured to shew that it finds no support whatever from the Newtonian writings, we shall not detain our readers with entering into any farther argument upon the paper now before us. The Doctor supports what he is pleased to call his propositions, partly by loose and strained reasoning, partly by reference to the demonstrations to be found in other authors. By a singular figure of speech – a sort of licence which we presume is peculiar to the dealers in hypotheses, the Doctor refers to an unpublished work of his own, under the title of ‘Young’s Syllabus.’ By a still more singular condescension, he tells us, in page 48, that it would be invidious, without necessity, to enumerate all the unsurmountable objections to the Newtonian theory of light; and although he insinuates that Sir Isaac Newton was but a sorry philosopher, and that he, Dr Young, has suddenly overthrown his system, he candidly admits that Sir Isaac was a tolerably good maker of experiments.

We take our leave of this paper, with recommending it to the Doctor to do that which he himself says would be very easy; namely, to invent various experiments upon this subject. As, however, the season is not favourable for optical observation, we recommend him to employ his winter months in reading the Optics, and some of the plainer parts of the Principia, and then to begin his experiments by repeating those which are to be found in the former of these works. If, after that, the making of discoveries and building of systems should appear as easy as he seems at present to think it, he may proceed to apply the skill which he has learned, with that caution which becomes a true philosopher; and give the results to the world with a no less becoming modesty, of which the Newtonian writings may have affording him the most signal examples.