Popular Science Monthly/Volume 4/March 1874/Replies to the Quarterly Reviewers



WITH the concluding paragraph of the previous article replying to criticisms I had hoped to end, for a long time, all controversial writing. But, while it was in the printer's hands, two criticisms, more elaborate than those dealt with above, made their appearance; and, now that the postponed publication of this latter half of the article affords the opportunity, I cannot, without risking misinterpretations, leave these criticisms unnoticed.

Especially do I feel called upon by courtesy to make some response to one who, in the Quarterly Review, for October, has dealt with me in a spirit which, though largely antagonistic, is not wholly unsympathetic, and who manifestly aims to estimate justly the views he opposes. In the space at my disposal, I cannot of course follow him through all the objections he has urged. I must content myself with brief comments on the two propositions he undertakes to establish. His enunciation of these runs as follows:

"We would especially direct attention to two points, to both of which we are confident objections may be made; and, although Mr. Spencer has himself doubtless considered such objections (and they may well have struck many of his readers also), we nevertheless do not observe that he has anywhere noticed or provided for them.

"The two points we select are:

"1. That his system involves the denial of all truth.

"2. That it is radically and necessarily opposed to all sound principles of morals."

On this passage, ending in these two startling assertions, let me first remark that I am wholly without this consciousness the reviewer ascribes to me. Remembering that I have expended some little labor in developing what I conceive to be a system of truths, I am somewhat surprised by the supposition that "the denial of all truth" is an implication which I am "doubtless" aware may be alleged against this system. Remembering, too, that by its programme this system is shown to close with two volumes on "The Principles of Morality," the statement that it is "necessarily opposed to all sound principles of morals" naturally astonishes me, and still more the statement that I am doubtless conscious it may be so regarded. Saying thus much by way of repudiating that latent skepticism attributed to me by the reviewer, I proceed to consider what he says in proof of these propositions.

On those seeming incongruities of Transfigured Realism commented on by him, I need say no more than I have already said in reply to Mr. Sidgwick, by whom also they have been alleged. I will limit myself to the corollary he draws from the doctrine of the Relativity of Knowledge, as held by me. Rightly pointing out that I hold this in common with "Messrs. Mill, Lewes, Bain, and Huxley," but not adding, as he should have done, that I hold it in common with Hamilton, Mansel, and the long list of predecessors through whom Hamilton traced it, the reviewer proceeds to infer from this doctrine of relativity that no absolute truth of any kind can be asserted—not even the absolute truth of the doctrine of relativity itself. And then he leaves it to be supposed by his reader that this inference tells especially against the system he is criticising. If, however, the reviewer's inference is valid, this "denial of all truth" must be charged against the doctrines of thinkers called orthodox, as well as against the doctrines of those many philosophers, from Aristotle down to Kant, who have said the same thing. But now I go further, and reply that, against that form of the doctrine of relativity held by me, this allegation cannot be made with the same effect as it can against preceding forms of the doctrine. For I diverge from other relativists in asserting that the existence of a non-relative is not only a positive deliverance of consciousness, but a deliverance transcending in certainty all. others whatever, and is one without which the doctrine of relativity cannot be framed in thought. I have urged that, "unless a real Non-relative or Absolute be postulated, the Relative itself becomes absolute, and so brings the argument to a contradiction;"[1] and elsewhere I have described this consciousness of a Non-relative manifested to us through the Relative as "deeper than demonstration—deeper even than definite cognition deep as the very nature of mind;"[2] which seems to me to be saying as emphatically as possible that, while all other truths may be held as relative, this truth must be held as absolute. Yet, strangely enough, though contending thus against the pure relativists, and holding with the reviewer, that "every asserter of such a (purely-relative) philosophy must be in the position of a man who saws across the branch of a tree on which he actually sits, at a point between himself and the trunk,"[3] I am singled out by him as though this were my own predicament. So far, then, from admitting that the view I hold "involves the denial of all truth," I assert that, having at the outset posited the coexistence of subject and object as a deliverance of consciousness which precedes all reasoning[4]—having subsequently shown, analytically, that this postulate is in every way verified,[5] and that in its absence the proof of relativity is impossible—my view is distinguished by an exactly-opposite trait.

The justification of his second proposition the reviewer commences by saying that "in the first place the process of Evolution, as understood by Mr. Spencer, compels him to be at one with Mr. Darwin in his denial of the existence of any fundamental and essential distinction between Duty and Pleasure." Following this by a statement respecting the genesis of moral sentiments as understood by me (which is extremely unlike the one I have given in the "Principles of Psychology" (§ 215, §§ 503-512, and §§ 524-532), the reviewer goes on to say that "we yield with much reluctance to the necessity of affirming that Mr. Spencer gives no evidence of ever having acquired a knowledge of the meaning of the term 'morality,' according to the true sense of the word."

Just noting that, as shown by the context, the assertion thus made is made against all those who hold the Doctrine of Evolution in its unqualified form, I reply that, in so far as it concerns me, it is one the reviewer would scarcely have made had he more carefully examined the evidence—not limiting himself to those works of mine named at the head of his article. And I cannot but think that, had the spirit of fairness, which he evidently strives to maintain, been fully awake when these passages were written, he would have seen that, before making so serious an allegation, wider inquiry was needful. If he had simply said that, given the doctrine of mental evolution as held by me, he failed to see how moral principles were to be established, I should not have objected; provided he had also said that I believe they can be established, and had pointed out what I hold to be their bases. As it is, however, he has so presented his own inference from my premises as to make it seem an inference which I also must draw from my premises. Quite a different and much more secure foundation for moral principles is alleged by me than that afforded by moral sentiments and conceptions, which he refers to as though they formed the sole basis of the ethical conclusions I hold. While the reviewer contends that "Mr. Spencer's moral system is even yet more profoundly defective, as it denies any objective distinction between right and wrong in any being, whether men are or are not responsible for their actions," I contend, contrariwise, that it is distinguished from other moral systems by asserting the objectivity of the distinction, and by endeavoring to show that the subjective distinction is derived from the objective distinction. In my first work, "Social Statics," published twenty-three years ago, the essential thesis is that, apart from their warrant as alleged Divine injunctions, and apart from their authority as moral intuitions, the principles of justice are primarily deducible from the laws of life, as carried on under social conditions. I argued throughout that these principles so derived have a supreme authority, to which considerations of immediate expediency must yield, and I was for this reason classed by Mr. Mill as an anti-utilitarian. More recently, in a letter drawn from me by this misapprehension of Mr. Mill, and afterward published by Prof. Bain in his "Mental and Moral Science," I have restated this position. Already, in an explanatory article entitled "Morals and Moral Sentiments," published in this Review for April, 1871, I have quoted passages from that letter; and here, considering the gravity of the assertions made by the Quarterly reviewer, I hope to be excused for requoting them:

"Morality, properly so called—the science of right conduct—has for its object to determine how and why certain modes of conduct are detrimental, and certain other modes beneficial. These good and bad results cannot be accidental, but must be necessary consequences of the constitution of things; and I conceive it to be the business of Moral Science to deduce, from the laws of life and the conditions of existence, what kinds of action necessarily tend to produce happiness, and what kinds to produce unhappiness. Having done this, its deductions are to be recognized as laws of conduct, and are to be conformed to irrespective of a direct estimation of happiness or misery."


"If it is true that pure rectitude prescribes a system of things far too good for men as they are, it is not less true that mere expediency does not of itself tend to establish a system of things any better than that which exists. While absolute morality owes to expediency the checks which prevent it from rushing into Utopian absurdities, expediency is indebted to absolute morality for all stimulus to improvement. Granted that we are chiefly interested in ascertaining what is relatively right, it still follows that we must first consider what is absolutely right; since the one conception presupposes the other."

And the comment I then made on these passages I may make now, that "I do not see how there could well be a more emphatic assertion that there exists a primary basis of morals independent of, and in a sense antecedent to, that which is furnished by experiences of utility, and consequently independent of, and in a sense antecedent to, those moral sentiments which I conceive to be generated by such experiences." I will only add that, had my beliefs been directly opposite to those I have enunciated, the reviewer might, I think, have found good reasons for his assertion. If, instead of demurring to the doctrine that "greatest happiness should be the immediate aim of man,"[6] I had indorsed that doctrine—if, instead of explaining and justifying "a belief in the special sacredness of these highest principles, and a sense of the supreme authority of the altruistic sentiments answering to them,"[7] I had denied the sacredness and the supreme authority—if, instead of saying of the wise man that "the highest truth he sees he will fearlessly utter, knowing that, let what may come of it, he is thus playing his right part in the world,"[8] I had said that the wise man will not do—this the reviewer might with some truth have described me as not understanding "the term 'morality' according to the true sense of the word." And he might then have inferred that the Doctrine of Evolution, as I hold it, implies denial of the "distinction between Duty and Pleasure." But, as it is, I think the evidence will not generally be held to warrant his assertion.

I quite agree with the reviewer that the prevalence of a philosophy "is no mere question of speculative interest, but is one of the highest practical importance." I join him, too, in the belief that "calamitous social and political changes" may be the outcome of a mistaken philosophy. Moreover, writing as he does under the conviction that there can be no standard of right and wrong save one derived from a Revelation interpreted by an Infallible Authority, I can conceive the alarm with which he regards so radically-opposed a system. Though I could have wished that the sense of justice he generally displays had prevented him from ignoring the evidence I have above given, I can understand how, from his point of view, the Doctrine of Evolution, as I understand it, "seems absolutely fatal to every germ of morality," and "entirely negatives every form of religion." But I am unable to understand that modified doctrine of Evolution which the reviewer proposes as an alternative. For, little as the reader would anticipate it after these expressions of profound dissent, the reviewer displays such an amount of agreement as to suggest that the system he is criticising might be converted, "rapidly and without violence, into an 'allotropic state,' in which its conspicuous characters would be startlingly diverse from those that it exhibits at present." May I, using a different figure, suggest a different transformation, having a subjective instead of an objective character? As, in a stereoscope, the two views, representing diverse aspects, often yield at first a jumble of conflicting impressions, but after a time suddenly combine into a single whole which stands out quite clearly, so, may it not be that the seemingly-inconsistent Idealism and Realism dwelt on by the reviewer, as well as the other seemingly-fundamental incongruities he is struck by, will, under more persistent contemplation, unite as complementary sides of the same thing?

My excuse, for devoting so much space to a criticism of so entirely different a kind as that contained in the British Quarterly Review for October, must be that, under the circumstances, I cannot let it pass unnoticed without seeming to admit its validity.

Saying that my books should be dealt with by specialists, and tacitly announcing himself as an expert in Physics, the reviewer takes me to task both for errors in the statement of physical principles and for erroneous reasoning in physics. That he discovers no mistakes I do not say. It would be marvelous if, in such a multitude of propositions, averaging a dozen per page, I had made all criticism-proof. Several are inadvertencies which I should have been obliged to the reviewer for pointing out as such, but which he prefers to instance as proving my ignorance. In other cases, taking advantage of an imperfection of statement, he proceeds to instruct me about matters which either the context, or passages in the same volume, show to be quite familiar to me. Here is a sample of his criticisms belonging to this class:

"Nor should we counsel a man to venture upon physical speculations who converts the proposition 'heat is insensible motion' into 'insensible motion is heat,' and hence concludes that when a force is applied to a mass so large that no motion is seen to result from it, or when, as in the case of sound, motion gets so dispersed that it becomes insensible, it turns to heat."

Respecting the first of the two statements contained in this sentence, I will observe that the reader, if not misled by the quotation-marks into the supposition that I have made, in so many words, the assertion that "insensible motion is heat," will at any rate infer that this assertion is distinctly involved in the passage named. And he will infer that the reviewer would never have charged me with such an absurd belief, if there was before him evidence proving that I have no such belief. What will the reader say, then, when he learns, not simply that there is no such statement, and not simply that on the page referred to, which I have ascertained to be the one intended, there is no such implication visible, even to an expert (and I have put the question to one), but when he further learns that, in other passages, the fact that heat is the one only of modes of insensible motion is distinctly stated (see "First Principles," §§ 66, 68, 171), and when he learns that elsewhere I have specified the several forms of insensible motion? If the reviewer, who looks so diligently for flaws as to search an essay in a volume he is not reviewing to find one term of an incongruity, had sought with equal diligence to learn what I thought about insensible motion, he would have found in the "Classification of the Sciences," Table II., that insensible motion is described by me as having the forms of heat, light, electricity, magnetism. Even had there been, in the place he names, an unquestionable implication of the belief which he ascribes to me, fairness might have led him to regard it as an oversight, when he found it at variance with statements I have elsewhere made. What, then, is to be thought of him when, in the place named, no such belief is manifest, either to an ordinary reader or a specially-instructed reader?

No less significant is the state of mind betrayed in the second clause of the reviewer's sentence. By representing me as saying that, when the motion constituting sound "gets so dispersed that it becomes insensible, it turns to heat," does he intend to represent me as thinking that, when sound-undulations become too weak to be audible, they become heat-undulations? If so, I reply that the passage he refers to has no such meaning. Does he then allege that some part of the force diffused in sound-waves is expended in generating electricity, by the friction of heterogeneous substances (which, however, eventually lapses from this special form of molecular motion in that general form constituting heat), and that I ought to have thus qualified my statement? If so, he would have had me commit a piece of scientific pedantry hindering the argument. If he does not mean either of these things, what does he mean? Does he contest the truth of the hypothesis which enabled Laplace to correct Newton's estimate of the velocity of sound—the hypothesis that heat is evolved by the compression each sound-wave produces in the air? Does he deny that the heat so generated is at the expense of so much wave-motion lost? Does he question the inference that some of the motion embodied in each wave is from instant to instant dissipated, partly in this way and partly in the heat evolved by fluid friction? Can he show any reason for doubting that, when the sound-waves have become too feeble to affect our senses, their motion still continues to undergo this transformation and diminution until it is all lost? If not, why does he implicitly deny that the molar motion constituting sound eventually disappears in producing the molecular motion constituting heat?[9] I will dwell no longer on the exclusively-personal questions raised by the reviewer's statements, but, leaving the reader to judge of the rest of my "stupendous mistakes" by the one I have dealt with, I will turn to a question worthy to occupy some space, as having an impersonal interest—the question, namely, respecting the nature of the warrant we have for asserting ultimate physical truths. The contempt which, as a physicist, the reviewer expresses for the metaphysical exploration of physical ideas, I will pass over with the remark that every physical question, probed to the bottom, ends in a metaphysical one, and that I should have thought the controversy now going on among chemists, respecting the legitimacy of the atomic hypothesis, might have shown him as much. On his erroneous statement that I use the phrase "Persistence of Force" as an equivalent for the now-generally-accepted phrase "Conservation of Energy," I will observe only that, had he not been in so great a hurry to find inconsistencies, he would have seen why, for the purposes of my argument, I intentionally use the word Force: Force being the generic word, including both that species known as Energy, and that species by which Matter occupies space and maintains its integrity—a species which, whatever may be its relation to Energy, and however clearly recognized as a necessary datum by the theory of Energy, is not otherwise considered in that theory. I will confine myself to the proposition, disputed at great length by the reviewer, that our cognition of the Persistence of Force is a priori. He relies much on the authority of Prof. Tait, whom he twice quotes to the effect that—

"Natural philosophy is an experimental, and not an intuitive science. No a priori reasoning can conduct us demonstratively to a single physical truth."

Were I to take an hypercritical attitude, I might dwell on the fact that Prof. Tait leaves the extent of his proposition somewhat doubtful, by speaking of "Natural philosophy" as one science. Were I to follow further the reviewer's example, I might point out that "Natural philosophy," in that Newtonian acceptation adopted by Prof. Tait, includes Astronomy; and, going on to ask what astronomical "experiments" those are which conduct us to astronomical truths, I might then "counsel" the reviewer not to depend on the authority of one who (to use the reviewer's polite language) "blunders" by confounding experiment and observation. I will not, however, thus infer from Prof. Tait's imperfection of statement that he is unaware of the difference between the two; and shall rate his authority as of no less value than I should had he been more accurate in his expression. Respecting that authority I shall simply remark that, if the question had to be settled by the authority of any physicist, the authority of one who is diametrically opposed to Prof. Tait on this point, and who has been specially honored, both by the Royal Society and by the French Institute, might well counterweigh his, if not outweigh it. I am not aware, however, that the question is one in Physics. It seems to me a question respecting the nature of proof. And, without doubting Prof. Tait's competence in Logic and Psychology, I should decline to abide by his judgment on such a question, even were there no opposite judgment given by a physicist, certainly of not less eminence.

Authority aside, however, let us discuss the matter on its merits. In the "Treatise on Natural Philosophy," by Profs. Thomson and Tait, § 243, I read that, "as we shall show in our chapter on 'Experience,' physical axioms are axiomatic to those only who have sufficient knowledge of the action of physical causes to enable them to see at once their necessary truth." In this I agree entirely. It is in Physics, as it is in Mathematics, that, before necessary truths can be grasped, there must be gained, by individual experience, such familiarity with the elements of the thoughts to be framed that propositions about those elements may be mentally represented with distinctness. Tell a child that things which are equal to the same thing are equal to one another, and the child, lacking a sufficiently abstract notion of equality, and lacking, too, the needful practice in comparing relations, will fail to grasp the axiom. Similarly, a rustic, never having thought much about forces and their results, cannot form a definite conception answering to the axiom that action and reaction are equal and opposite. In the last case, as in the first, ideas of the terms and their relations require to be made, by practice in thinking, so vivid that the involved truths may be mentally seen. But when the individual experiences have been multiplied enough to produce distinctness in the representations of the elements dealt with, then, in the one case, as in the other, those mental forms, generated by ancestral experiences, cannot be occupied by the elements of one of these ultimate truths without perception of its necessity. If Prof. Tait does not admit this, what does he mean by speaking of "physical axioms" and by saying that the cultured are enabled "to see at once their necessary truth?"

Again, if there are no physical truths which must be classed as a priori, I ask why Prof. Tait joins Sir W. Thomson in accepting, as bases for Physics, Newton's Laws of Motion? Though Newton gives illustrations of prolonged motion in bodies that are little resisted, he gives no proof that a body in motion will continue moving, if uninterfered with, in the same direction at the same velocity; nor, on turning to the enunciation of this law, quoted in the above-named work, do I find that Prof. Tait does more than exemplify it by facts which can themselves be asserted only by taking the law for granted. Does Prof. Tait deny that the first law of motion is a physical truth? If so, what does he call it? Does he admit it to be a physical truth, and, denying that it is a priori, assert that it is established a posteriori—that is, by conscious induction from observation and experiment? If so, what is the inductive reasoning which can establish it? Let us glance at the several conceivable arguments which we must suppose him to rely on.

A body set in motion soon ceases to move if it encounters much friction, or much resistance from other bodies struck. If less of its energy is expended in moving, or otherwise affecting, other bodies, or in overcoming friction, its motion continues longer. And it continues longest when, as over smooth ice, it meets with the smallest amount of obstruction from other matter. May we then, proceeding by the method of concomitant variations, infer that were it wholly unobstructed its motion would continue undiminished? If so, we assume that the diminution of its motion observed in experience is proportionate to the amount of energy abstracted from it in producing other motion, either molar or molecular. We assume that no variation has taken place in its rate, save that caused by deductions in giving motion to other matter; for, if its motion be supposed to have otherwise varied, the conclusion, that the differences in the distances traveled result from differences in the obstructions met with, is vitiated. Thus the truth to be established is already taken for granted in the premises. Nor is the question begged in this way only. In every case where it is remarked that a body stops the sooner, the more it is obstructed by other bodies or media, the law of inertia is assumed to hold in the obstructing bodies or media. The very conception of greater or less retardation so caused, implies the belief that there can be no retardations without proportionate retarding causes; which is itself the assumption otherwise expressed in the first law of motion.

Again, let us suppose that, instead of inexact observations made on the movements that occur in daily experience, we make exact experiments on movements specially arranged to yield measured results; what is the postulate underlying every experiment? Uniform velocity is defined as motion through equal spaces in equal times. How do we measure equal times? By an instrument which can be inferred to mark equal times only if the oscillations of the pendulum are isochronous; which they can be proved to be only if the first and second laws of motion are granted. That is to say, the proposed experimental proof of the first law assumes not only the truth of the first law, but of that which Prof. Tait agrees with Newton in regarding as a second law. Is it said that the ultimate time-measure referred to is the motion of the Earth round its axis, through equal angles in equal times? Then, the obvious rejoinder is, that the assertion of this similarly involves an assertion of the truth to be proved; since the undiminished rotatory movement of the Earth is itself a corollary upon the first law of motion. Is it alleged that this axial movement of the Earth through equal angles in equal times is ascertainable by reference to the stars? I answer, that a developed system of Astronomy, leading through complex reasonings to the conclusion that the Earth rotates, is, in that case, supposed to be needful before there can be established a law of motion which this system of Astronomy itself postulates. For, even should it be said that the Newtonian theory of the Solar System is not necessarily presupposed, but only the Copernican, still the proof of this assumes that a body at rest (a star being taken as such) will continue at rest; which is a part of the first law of motion, regarded by Newton as not more self-evident than the remaining part.

Not a little remarkable, indeed, is the oversight made by Prof. Tait, in asserting that "no a priori reasoning can conduct us demonstratively to a single physical truth," when he has before him the fact that the system of physical truths constituting Newton's "Principia," which he has joined Sir William Thomson in editing, is established by a priori reasoning. That there can be no change without a cause, or, in the words of Mayer, that "a force cannot become nothing, and just as little can a force be produced from nothing," is that ultimate dictum of consciousness on which all physical science rests. It is involved alike in the assertion that a body at rest will continue at rest, in the assertion that a body in motion must continue to move at the same velocity in the same line if no force acts upon it, and in the assertion that any divergent motion given to it must be proportionate to the deflecting force; and it is also involved in the axiom that action and reaction are equal and opposite.

The reviewer's doctrine, in support of which he cites against me the authority of Prof. Tait, illustrates in Physics that same error of the inductive philosophy which, in Metaphysics, I have pointed out elsewhere ("Principles of Psychology," Part VII.). It is a doctrine implying that we can go on forever asking the proof of the proof, without finally coming to any deepest cognition which is unproved and unprovable. That this is an untenable doctrine I need not say more to show. Nor, indeed, would saying more to show it be likely to have any effect, in so far at least as the reviewer is concerned; seeing that he thinks I am "ignorant of the very nature of the principles" of which I am speaking, and seeing that my notions of scientific reasoning "remind" him "of the Ptolemists," who argued that the heavenly bodies must move in circles because the circle is the most perfect figure.[10]

Not to try the reader's patience further, I will end by pointing out that, even were the reviewer's criticisms all valid, they would leave unshaken the system he contends against. Though one of his sentences (page 480) raises the expectation that he is about to assault, and greatly to damage, the fabric of propositions contained in the second part of "First Principles," yet all those propositions which constitute the fabric he leaves not only uninjured but even untouched, contenting himself with trying to show (with what success we have seen) that the fundamental one is an a posteriori truth, and not an a priori truth. Against the general Doctrine of Evolution, considered as an induction from all concrete phenomena, he utters not a word; nor does he utter a word to disprove any one of those laws of the redistribution of matter and motion by which the process of Evolution is deductively interpreted. Respecting the law of the Instability of the Homogeneous, he says no more than to quarrel with one of the illustrations. He makes no criticism on the law of the Multiplication of Effects. The law of Segregation he does not even mention. Nor does he mention the law of Equilibration. Further, he urges nothing against the statement that these general laws are severally deducible from the ultimate law of the Persistence of Force. Lastly, he does not deny the Persistence of Force, but only differs respecting the nature of our warrant for asserting it. Beyond pointing out here a cracked brick, and there a coin set askew, he merely makes a futile attempt to show that the foundation is not natural rock, but concrete. From his objections I may, indeed, derive much satisfaction. That a competent critic, obviously anxious to do all the mischief he can, and not over-scrupulous about the means he uses, has done so little, may be taken as evidence that the fabric of conclusions attacked will not be readily overthrown.

  1. "First Principles," § 26.
  2. Ibid., § 62.
  3. Compare "Principles of Psychology," §§ 88, 95, 391, 401, 406.
  4. "First Principles," §§ 39, 45.
  5. "Principles of Psychology," part vii.
  6. "Social Statics," chapter iii.
  7. "Principles of Psychology," § 631.
  8. "First Principles," § 34.
  9. Only after the foregoing paragraphs were written, did the remark of a distinguished friend show me how certain words were misconstrued by the reviewer in a way that had never occurred to me as possible. In the passage referred to, I have said that sound-waves "finally die away in generating thermal undulations that radiate into space;" meaning, of course, that the force embodied in the sound-waves is finally exhausted in generating thermal undulations. In common speech, the dying away of a prolonged sound, as that of a church-bell, includes its gradual diminution as well as its final cessation. But, rather than suppose I gave to the words this ordinary meaning, the reviewer supposes me to believe, not simply that the longitudinal waves of air can pass, without discontinuity, into the transverse waves of ether, but he also debits me with the belief that the one order of waves, having lengths measurable in feet, and rates expressed in hundreds per second, can by mere enfeeblement pass into the other order of waves, having lengths of some fifty thousand to the inch, and rates expressed in many billions per second! Why he preferred so to interpret my words, and that, too, in the face of contrary implications elsewhere (instance § 100), will, however, be manifest to every one who reads his criticisms.
  10. Other examples of these amenities of controversy, in which I decline to imitate my reviewer, have already been given. What occasions he supplies me for imitation, were I minded to take advantage of them, an instance will show. Pointing out an implication of certain reasonings of mine, he suggests that it is too absurd even for me to avow explicitly, saying: "We scarcely think that even Mr. Spencer will venture to claim as a datum of consciousness the Second Law of Motion, with its attendant complexities of component velocities," etc. Now, any one who turns to Newton's "Principia" will find that to the enunciation of the Second Law of Motion nothing whatever is appended but an amplified restatement there is not even an illustration, much less a proof. And from this law, this axiom, this immediate intuition or "datum of consciousness," Newton proceeds forthwith to draw those corollaries respecting the composition of forces which underlie all dynamics. What, then, must be thought of Newton, who explicitly assumes that which the reviewer thinks it absurd to assume implicitly?