the respectability of the witnesses, and, with full confidence in their integrity, estimate the real value of their assertion, which amounts to this: they were not conscious of pushing. We now see that the fact, which was imagined to be simple, namely, that "the persons did not push," turns out to be excessively dubious, namely, "they were not conscious of pushing." If we come to examine such a case, we find Physiology in possession of abundant examples of muscular action accompanied by no distinct. consciousness, and some of these examples are very similar to those of the unconscious pushing, which may have turned the table; and we are thus satisfied of three important points:1. Pushing is an adequate cause, and will serve to explain the movement of the table, as well as either the supposed spirit or electricity. 2. Pushing may take place without any distinct consciousness on the part of those who push. 3. Expectant attention is known to produce such a state of the muscles as would ocoasion this unconscious pushing.

Considered therefore as a mere hypothesis, this of unconscious pushing is strictly scientific; it may not be true, but it has fulfilled the preliminary conditions. Unlike the two hypotheses it opposes, it assumes nothing previously unknown, or not easily demonstrable; every position has been verified; whereas the metaphysicians have not verified one of their positions: they have not proved the presence of their agents, nor have they proved that these agents, if present, would act in the required manner. Of spirit we know nothing, consequently can predicate nothing. Of electricity we know something, but what is known is not in accordance with the table-turning hypothesis. Of pushing we know that it can and does turn tables. All then that is required to convert this latter hypothesis into scientific certainty, is to prove the presence of the pushing in this particular case. And it is proved in many ways, positive and negative, as I showed when the phenomenon first became the subject of public investigation. Positive, because if the hands rest on a loose tablecloth, or on substances with perfectly smooth surfaces which will glide easily over the table, the cloth or the substances will move, and not the table. Negative, because if the persons are duly warned of their liability to unconscious pushing, and are

told to keep vigilant guard over their sensations, they do not move the table, although previously they have moved it frequently. When we have thus verified the presence of unconscious pushing, all the links in the chain have been verified, and certainty is complete.

Reviewing the three explanations which the phenomenon of table-turning called forth, we elicit one characteristic as distinguishing the scientific Method, namely, the verification of each stage in the process, the guaranteeing of each separate point, the cultivated caution of proceeding to the unknown solely through the avenues of the known. The germinal difference, then, be`tween the metaphysical and scientific Methods, is not that they draw their explanations from a different source, the one employing Reasoning where the other employs Observation, but that the one is content with an explanation which has no further guarantee than is given in the logical explanation of the difficulty; whereas the other imperatively demands that every assumption should be treated as provisional, hypothetical, until it has been confronted with fact, tested by acknowledged tests, in a word, verified. The guarantee of the metaphysician is purely logical, subjective: it is the intellectus sibi permissus; the guarantee of the other is derived from a correspondence of the idea with experience. As Bacon says, all merely logical explanations are valueless, the subtlety of nature greatly surpassing that of argument: "Subtilitas naturæ subtilitatem argumentandi multis partibus superat;" and he further says, with his usual felicity, "Sed axiomata à particularibus ritè et ordine abstracta nova particularia rursus facilè indicant et designant." It is these "new particulars" which are reached through those already known, and complete the links of the causal chain.

Open the history of Science at any chapter you will, and its pages will show how all the errors which have gained acceptance gained it because this important principle of verification of particulars was neglected. Incessantly the mind of man leaps forward to "anticipate" Nature, and is satisfied with such anticipations if they have a logical consistence. When Galen and Aristotle thought that the air circulated in the arteries, causing the pulse to beat, and cooling the temperature of the blood, they

were content with this plausible anticipation; they did not verify the facts of the air's presence, and its cooling effect; when they said that the "spirituous blood" nourished the delicate organs, such as the lungs, and the "venous blood" nourished the coarser organs, such as the liver; when they said that the "spirit," which was the purer element of the blood, was formed in the left ventricle, and the venous blood in the right ventricle, they contented themselves with unverified assumptions. In like manner, when in our own day physiologists of eminence maintain that in the organism there is a Vital Force which suspends chemical actions, they content themselves with a metaphysical unverified interpretation of phenomena. If they came to rigorous confrontation with fact, they would see that so far from chemical action being "suspended" it is incessantly at work in the organism; the varieties observable being either due to a difference of conditions (which will produce varieties out of the organism), or to the fact that the action is masked by other actions.

If the foregoing discussion has carried with it the reader's assent, he will perceive that the distinguishing characteristic of Science is its Method of graduated Verification, and not, as some think, the employment of Induction in lieu of Deduction. All Science is deductive, and deductive in proportion to its separation from ordinary knowledge, and its co-ordination into systematic Science. "Although all sciences tend to become more and more deductive," says a great authority, "they are not therefore the less inductive; every step in the deduction is still an induction. The opposition is not between the terms Inductive and Deductive, but between Deductive and Experimental."* Experiment is the great instrument of Verification. The difference between the ancient and modern philosophies lies in the facility with which the one accepted axioms and hypotheses as the basis for its deductions, and the cultivated caution with which the other insists on verifying its axioms and hypotheses before

* Mill's System of Logic: perhaps the greatest contribution to English speculation since Locke's Essay. Had Mr. Mill invented a new terminology and expressed himself with less clearness, he would assuredly have gained that reputation for profundity which, by a thorough misconception of the nature of thought, is so often awarded to obscurity.

deducing conclusions from them. We guess as freely as the ancients; but we know that we are guessing; and if we chance to forget it, our rivals quickly remind us that our guess is not evidence. Without guessing, Science would be impossible. We should never discover new islands, did we not often venture seawards with intent to sail beyond the sunset. To find new land, we must often quit sight of land. As Mr. Thompson admirably expresses it :-"Philosophy proceeds upon a system of credit, and if she never advanced beyond her tangible capital, our wealth would not be so enormous as it is."* While both metaphysician and man of science trade on a system of credit, they do so with profoundly different views of its aid. The metaphysician is a merchant who speculates boldly, but without that convertible. capital which can enable him to meet his engagements. He gives bills, yet has no gold, no goods to answer for them; these bills are not representative of wealth which exists in any warehouse. Magnificent as his speculations seem, the first obstinate creditor who insists on payment makes him bankrupt. The man of science is also a venturesome merchant, but one fully alive to the necessity of solid capital which can on emergency be produced to meet his bills; he knows the risks he runs whenever that amount of capital is exceeded; he knows that bankruptcy awaits him if capital be not forthcoming.

The contrast therefore between Philosophy and Science, or Metaphysics and Positive Philosophy, is a contrast of Method; but we must not suppose that the Method of the one is Deduction, while that of the other is Observation. Nothing can be more erroneous than the vulgar notion of the " Inductive Method," as one limited to the observation of facts. Every instructed thinker knows that facts of observation are particular theories; that is to say, every fact which is registered as an observation is constituted by a synthesis of sensation and inference. We shall see this illustrated presently. To it must be added the truth that Science is constantly making discoveries by Reasoning alone, aloof from any immediate exercise of Observation, aloof indeed from the very phenomena it classifies; for when facts are regis

*Outlines of the Laws of Thought, p. 312.

tered in formulas, we resign ourselves to the manipulation of these formulas as symbols or equations, assured that the result will accord with Nature. Fresnel predicted the change in polarization from no observation of facts immediately lying before him, but from a happy elucidation of algebraic symbols. Astronomy is more studied on paper than through the telescope, which however is called upon to verify the results figured on paper. So that if we compare our astronomical and geological theories with the cosmical speculations of a Plato or a Hegel, we shall not find them deficient in the speculative daring which outruns the slow process of observation, but we shall find the difference to lie initially in the rigor with which our deductive formulas are established, and in the different estimates we form of what is valid evidence.

Galileo made Astronomy a science when he began to seek the unknown through the known, and to interpret celestial phenomena by those laws of motion which were recognized on the surface of the earth. Geology became possible as a science when its principal phenomena were explained by those laws of the action of water, visibly operating in every river, estuary, and bay. Except in the grandeur of its sweep, the mind pursues the same course in the interpretation of geological facts which record the annals of the universe, as in the interpretation of the ordinary incidents of daily life. To read the pages of the great Stonebook, and to perceive from the wet streets that rain has recently fallen, are the same intellectual processes. In the one case the mind traverses immeasurable spaces of time, and infers that the phenomena were produced by causes similar to those which have produced similar phenomena within recent experience; in the other case, the mind similarly infers that the wet streets and swollen gutters have been produced by the same cause we have frequently observed to produce them. Let the inference span with its mighty arch a myriad of years, or span but a few minutes, in each case it rises from the ground of certain familiar indications, and reaches an antecedent known to be capable of producing these indications. Both inferences may be wrong: the wet streets may have been wetted by a water-cart, or by the bursting of a pipe. We cast about for some other indication of