NATURE 



[May 5, 1 88 



position it may be brought to rest by the particular cir- 

 cumstances of his temperament and education. Thus it 

 is that to Prof. Cleland it appears most reasonable to 

 conclude that "in the evolutions of organisation there is 

 a non-material impulse," to which virtually we may refer 

 all difSculties that we cannot solve in our contemplation 

 of the natural process ; while to Mr. Darwin this method 

 of relegating any special question in science to an ultimate 

 theory of things amounts simply to "a re-statement of 

 the question." As a question of science no explanation 

 is furnished by this method, and whether or not in par- 

 ticular cases any such explanation is possible, men of 

 science, as stcch, must never assume, as by following the 

 method in question they would assume, that such 

 explanation is impossible. 



Therefore, so long as men of science are watchfully 

 careful never, as Prof. Cleland phrases it, " to make final 

 do the duty of efficient causes," so long it matters not to 

 science what views her individual cultivators may hold 

 on super-scientific questions. Only it is certain that a 

 man strongly imbued with belief in final causes is apt to 

 incur the danger of confusing them with efficient causes, 

 and a striking instance of this fact is displayed by Prof. 

 Cleland himself, where he says, " If evolutions are definite, 

 or, in other words, if morphological designs exist, the 

 necessity for explaining all affinity by genetic relationship 

 disappears." This we understand to mean that wherever 

 affinity cannot at once be seen due to " efficient causes," 

 we are at liberty forthwith to ascribe it to " final causes." 

 And this presents in as bad a form as ever the doctrine 

 which for centuries has paralysed the movements of 

 science. If a scientific man of to-day wishes to retain 

 his belief in "morphological design," it must be as a 

 belief in some wholly transcendental principle with which 

 science has nothing whatever to do. Otherwise he fails 

 in scientific method, as for instance Prof. Cleland fails 

 where he points to " sex and symmetry" as due to design, 

 only because he does not see how they can be due to 

 natural selection. It makes not an atom of difference to 

 the logical position of science whether or not the fact of 

 sex or symmetry, or any other fact to which any writer 

 can point, is inexplicable by natural selection. The 

 logical position of science is that if such facts are not due 

 to natural selection, they must be due to some other 

 natural causes which we may reasonably hope some day 

 to ascertain. And if it is asked what is the justification 

 of this logical position to which science has been raided, 

 the answer is supplied by the history of science itself. 

 Let any one go through the writings of Paley, Bell, or 

 Chalmers, and strike out all the instances of " morpho- 

 logical design " which he plainly sees can now be explained 

 by natural selection, and he must be a very dull man if 

 he continues to repose any confidence in the residue as 

 evidence of causes other than strictly natural. In the 

 face of so immense an analogy the burden of proof lies 

 with the teleologists to show that any special cases to 

 which they may point as still requiring explanation are to 

 be regarded as inexplicable ; and this burden most 

 assuredly is not discharged by Prof. Cleland when he 

 seeks to strike at the heart of natural selection as a 

 natural cause by saying of heredity that in it he " can 

 only recognise a phenomenon the origin of which demands 

 an explanation." No doubt this explanation is demanded 



but is demanded at the hands of observation and experi- 

 ment — not from the cloudlands of " spirit which pervades 

 the whole." 



We have thought it well to devote the main part of this 

 review to the essay on Evolution, because the occasion 

 seems a suitable one to raise our voice against the per- 

 nicious habit of flirting with final causes which still lingers 

 among a certain section of scientific workers. Let any 

 one who so may wish continue to believe in final causes ; 

 but if he does not also wish to clog the wheels of science, 

 let him cease to throw his final causes into any gap which 

 the roads of inquiry may present. Science, as such, 

 requires no dens ex machiiid, and those of her votaries 

 who feel that they require him will best consult her 

 interests by laying the strongest possible emphasis upon 

 the ex. 



The most interesting of the other essays is that on 

 Expression. In a section devoted to " Permanent Ex- 

 pression," it is observed that while in many respects the 

 physical peculiarities of permanent expression admit of 

 being explained by obvious causes, in other respects this 

 is not so. Thus, for instance, " a massive chin is so dis- 

 tinctly a physiognomic representation of firmness, that an 

 artist would in vain attempt to exhibit the resolution of a 

 Cromwell in a face with a small and narrow jaw, or with 

 one of those pretty chins like a bagatelle ball, not un- 

 common in certain localities. . . . Yet the chin has no 

 physical function whatever, so far as I am aware." 



In a section on the " Expression of the Emotions,'' Dr. 

 Cleland argues in favour of an active principle which 

 may be defined as unconscious symbolism, and certainly 

 in the course of a few interesting and suggestive pages 

 he makes out a strong case. It is first shown that 

 language serves, as it were, to stereotype a number of 

 symbolic ideas, so that, for instance, words signifying 

 elevation come also to signify greatness, goodness, &c., 

 while we likewise " associate impressions derived through 

 the organs of sense with impressions from the moral world 

 similarly pleasant or otherwise, as in the case of sweetness, 

 bitterness, brightness, and gloom." Such associations 

 having become firmly established, the way is prepared 

 for their expression by gesture ; so that at last " the 

 workings of the mind are expressed by attitudes, gestures, 

 and movements of body of a nature correlative with 

 them." Thus " slight movements of the arms express 

 the hugging of an idea to the bosom when nothing but 

 what is thoroughly impersonal is thought of, and the 

 fingers bend as if to keep a something in the hand when 

 nothing but delightful sentiment is conceived." And 

 similarly the gesture of sweeping away, backwards, and 

 downwards a repulsive object from before the eyes, " is a 

 gesture applied to the intangible and invisible ; by it 

 the cleric puts away false doctrine, and the fastidious 

 sublim.ely brands a notion as vulgar." 



This theory, of which many other illustrations are 

 given, is to some extent the same as that which Mr. 

 Darwin calls " serviceable associated habits," seeing that 

 the principle of association is concerned in both ; but as 

 in Dr. Cleland's theory the association need not be 

 " serviceable," and as it is concerned with an unconsciously 

 symbolic representation of ideas, we think with him that 

 it deserves to be considered as a distinct theor)', and we 

 can scarcely doubt that the principle with which it is 



