ORDINARY MEETING, MARCH 4, 1867.

THE REV. WALTER MITCHELL, VICE-PRESIDENT, IN THE CHAIR.

The minutes of the previous Meeting were read and confirmed.

The HONORARY SECRETARY announced the names of the following new members and associates.

MEMBERS:- John Griffith, Esq., 6, Hanover Terrace, Regent's Park; W. Castle Smith, Esq., F.R.G.S., M.R.I., 1, Gloucester Terrace, Regent's Park (Life Members).

The Hon. Charles Barter, B.C.L. Oxon. (Member of the Legislative Council of Natal), Pietermaritzburg; the Rev. D. A. Beaufort, M.A., Warburton Rectory, Warrington; George Pigot Moodie, Esq., Gov. Surv., J. P., Melsetter, Pietermaritzburg, Natal; P. C. Sutherland, Esq., M.D., M.R.C.S. Edinburgh, F.R.G.S., Surv. Gen. Pietermaritzburg, Natal.

The above Members are on the Foundation List.

MEMBERS for 1867-R. G. M. Browne, Esq., 9, College Crescent, Hampstead; Thomas Lomas, Esq., H.M. Civil Service, Alma Villas, Windsor, Berks.

ASSOCIATES, 1ST CLASS :-W. F. Browell, Esq., Barrister-at-Law, J.P. for Kent, Broadlands, Tunbridge Wells; 2ND CLASS :-The Rev. Philip Dwyer, A.B., T.C.D., Vicar of Drumcliffe, Bindon Street, Ennis, Ireland; the Rev. Walter S. Grindle, Theol. Assoc. K.C.L., 26, Bessborough Street, Pimlico W. R. Warwick, Esq., M.D., Southend, Essex.

MR. WARINGTON then read the following Paper :

ON THE CREDIBILITY OF DARWINISM.-By GEORGE WARINGTON, Esq., F.C.S., Mem. Vict. Inst.

T is a rare circumstance for the full explanation of any phenomenon, or series of phenomena, in nature, to be discovered at once. In respect to the most certain, as well as the most uncertain of the interpretations of Science, there has been in nearly every case a period of speculation, of theorizing, in which the view ultimately accepted as true was merely an hypothesis. From the very nature of things it must be so. A certain interpretation is not to be arrived at without a widely-extended series of facts on which it may be based,-facts often requiring long and laborious investigation to accumulate. In such accumulation, carried on with the express purpose of obtaining an explanation, it is impossible but that various hypothetical explanations should suggest themselves to the inquirer, one of which will be almost certain to approve itself to his mind as the most probable. This immediately becomes his theory; to ascertain the truth or falsity of which is henceforth his object. It may be that further investigation disproves it, and it is cast aside; only, however, to be replaced by another, which, so far, stands the test of facts. Or it may be that fuller knowledge merely adds strength and solidity to that first adopted. But in either case it is through hypothesis that truth is ultimately attained. Theoretically, of course, the scientific method is first to obtain a full view of all the facts, and then deduce the explanation. Rarely, if ever, however, is this theory carried out in practice. Nor, indeed, can it be; since how, before any idea of the explanation exists, is it to be known what facts especially need to be accumulated and sought after? All that the severest Science can demand is that the result, when offered for acceptance as true, shall be capable of being cast into this theoretical mould; the facts when duly weighed and classified being shown exactly and inevitably to imply the explanation given. But that this should have been the actual course of the investigation-that Science has nothing whatever to do with. In a word, to use Darwinian language, the process by which true explanations are obtained in Science is very much one of Natural Selection. Many hypotheses spring up and struggle together for existence; passing on from hand to hand, they become varied and modified; each variation tending to produce harmony with the conditions of life (i.e. the facts of the case) favours prolonged existence; each

variation tending the other way leads to extinction; and so at last, hypothesis after hypothesis dying out, that one is left. alone as victor which is found to be most perfectly adapted to the exigencies of the case.

I have been led to these remarks upon the relation of hypotheses to scientific conclusions, 1st, because it is such an intermediate hypothesis which we have this evening to consider; and, 2nd, because it is sometimes said that to spend time in estimating the credibility of an unproved theory is unscientific, we should rather devote ourselves to the investigation of facts. But if the principles laid down above be correct, and it is practically impossible to conduct investigation without hypotheses, then it is clearly a matter of grave importance what hypotheses we thus tentatively adopt,-a matter which should of course be determined by the amount of credibility at present belonging to them. Some facts, some arguments, some analogies, bearing upon Darwinism, we have already, albeit confessedly insufficient to demonstrate its truth. The question is, then, do these facts, arguments and analogies afford such an amount of evidence in its favour as to render it a fair working hypothesis for future research? Is Darwinism, in a word, credible? Not, is it the true explanation of the phenomena it seeks to account for; but, is it such an hypothesis as may possibly in the end prove to be so? If so-if Darwinism be credible, then it ought to be carefully kept in mind, applied, and tested, in all investigations into the facts which it concerns, that so its truth or falsity may become apparent. If, on the other hand, Darwinism be incredible, then it may be at once rejected as unnecessary to be considered, at all events until fresh evidence in its favour is adduced. This is the practical issue which the present paper proposes to raise.

The tests to which scientific hypotheses are subject in the process of selection by which they pass into certain interpretations, are fourfold,-possibility, adequacy, consistency, and harmony. The precise meaning to be attached to these terms, and the value to be set upon the tests they denote, may be best seen by a simple example. Let us take for this purpose the hypothesis that gravitation is the sole controlling force by which the motions of the planets in the solar system are regulated. To test the credibility of this hypothesis we should have to inquire,-1st, Is gravitation a real cause, capable by its action of controlling planetary motion; i. e., is the hypothesis possible? 2nd, Is gravitation a sufficient cause to account for all the motions actually observed; i. e., is the hypothesis adequate? 3rd, Are all the effects in fact produced which

gravitation must produce if really at work; i. e., is the hypothesis consistent? 4th, Is there any evidence of gravitation. being actually at work in any part of the solar system, or other similar sphere, which would afford ground of analogy for regarding it as probably at work throughout the whole; i.e., is the hypothesis harmonious? Before any hypothesis can be admitted as certainly true, it must satisfy all these four requirements. Until it does so, it can only be accounted as more or less credible; provided always that it answers the first demand-that it is possible. If this be wanting-if there be no evidence that the cause assumed is a real cause, then the hypothesis is purely fanciful and unworthy of credence. But if it be possible, then so far as it fulfils the other three conditions it is also credible. The degree to which any hypothesis fulfils these conditions will depend primarily of course upon its truth; it will also, however, be affected very seriously by the inevitable limitations of human knowledge. It is quite possible for a true explanation to appear inadequate or inconsistent, simply because of our ignorance. Thus, to take an illustration bearing upon the example just reviewed, the adequacy of gravitation, prior to the discovery of Neptune, appeared at fault, perturbations being observed in the planetary motion, for which gravitation failed to account. The discovery of Neptune, which removed this objection, depended, however, on a property altogether independent of its gravitating influence, the property, namely, of reflecting light. Had Neptune been so constituted as not to reflect (which is perfectly possible), no telescope could have descried it, and gravitation might very likely in consequence have been rejected by some as an inadequate hypothesis, when, in truth, the apparent inadequacy arose entirely from the imperfection of our knowledge. It is plain, then, that no objection to an hypothesis should be regarded as of final weight, for which a possible explanation can be given, not inconsistent with observed facts. Weaken the credibility of the hypothesis such objections can and do, destroy it altogether they cannot. On these principles, then, it is proposed now briefly to discuss "the credibility of Darwinism."

1. Its possibility. Are the elements involved in Mr. Darwin's hypothesis real elements, and are they capable of producing the kind of effects he ascribes to them? The elements involved are four :-(1) "Growth with reproduction; (2) Inheritance which is almost implied by reproduction; (3) Variability from the indirect and direct action of the external conditions of life, and from use and disuse; (4) A ratio of increase so high as to lead to a struggle for life."

The result being "Natural selection, entailing divergence of character and the extinction of less improved forms."* Is it possible for these elements, in their mutual action and reaction, to occasion specific differences in living beings? This is our first inquiry; for the solution of which it is manifestly necessary that we should understand clearly what is meant by specific differences-what is meant by a species. We may define it roughly by saying that a species is a race of living beings differing in certain respects from all other races, such differences being steadily transmissible by reproduction, and not being the immediate result of present outward conditions. By this definition are excluded-(1) all mere transient sports, and (2) all apparent varieties dependent directly upon situation, climate, &c. To many it will doubtless seem far too lax a definition, as raising a large number of so-called varieties into the rank of species. Let such afford a better one, equally sufficient and equally free from arbitrary assertion. The great thing we have to beware of is allowing prejudice to lay down a definition which shall beg the question at issue, e. g., that specific differences are those which are permanently invariable; that species are those races which are not bound together with intermediate varieties, or which cannot be traced to a common origin, or which, when crossed, yield sterile hybrids. To discuss the natural origin of species with such definitions as the basis would be as impossible and absurd as to discuss the motions of the fixed stars with the definition given that the fixed stars are those which never move. The only fair definition of a species is a race of living beings possessing common characteristic differences from all others, which differences at the present time are constant and inherent.

That species grow and reproduce, that they pass on their characteristics by inheritance, and that they are liable to variation, is admitted by every one. The point at issue is whether they can so pass on and accumulate their variations by inheritance as in the end to bring about specific differences. If they can do so, then the Darwinian hypothesis of the origin of species is, so far, possible; variation and inheritance could bring about specific differences.

Our attention must in the first place be directed to the formation of breeds among domesticated animals and cultivated plants. It is notorious that there have been produced by the agency of man distinct races of living beings, having characteristic differences from all others, which differences

* "Origin of Species," 4th edit., p. 577.