408 Prof, Forbes on the evidence for a Physical Connexion 



just propensity of man's mind it is to reason thus; but the 

 science of numbers refuses its aid to estimate the arithmetical 

 force of such arguments. 



[1 7.] The impression of design deduced from symmetry is one 

 of the most striking which it is possible to suppose ; and yet, as 

 far as I know, it is impossible to represent the improbability that 

 it should be the result of chance. In fact, a symmetrical arrange- 

 ment, so far from being an improbable one, would, if Mitchell's 

 argument, were founded in reason, appear the most conform- 

 able to that most hazardous of the laws of hazard, the law of 

 sufficient reason. This I shall endeavour presently to illustrate 

 further. Meanwhile I observe that a symmetrical arrange- 

 ment of points placed "at random," being one of many random 

 ways of placing those points, all equally probable, would ap- 

 pear to have neither preference nor the contrary on the doc- 

 trines of chance*. And here we also notice the important 

 distinction already referred to, between an accomplished fact 

 and an event which is anticipated, though there would be 

 millions or even infinity to one against the probability of a 

 symmetrical arrangement; — once made, it takes a position (by 

 the laws of mere chance) as a result as probable as any other 

 arrangement which might have presented itself. But the eye 

 of reason can never acquiesce in this conclusion, from the 

 simple consideration of antecedent probabilities, t Were the 

 stars (for example) disposed in square or hexagonal order over 

 the entire sky, could we for a moment tolerate the conception 

 of a (6 random scattering," which (at first sight) appears con- 

 sistent enough with their actual distribution ; and does not 

 the occurrence of condensed groups or pairs of stars in some 

 places, and of great vacuities in others, seem to be rather the 

 rule of chance than its exception ? 



[18.] It is not many years since the idea of the foot-prints of 

 animals, which walked over the then soft surfaces of the older 

 rocks ages before man's creation, being yet in evidence, was 

 scouted as absurd: and it might have been so still had the 

 proof been to be sought solely in the clearness of the foot- 

 prints being those of an animal, differing as they no doubt 

 did from those of any species now existing. But the symmetry 



* " Les combinaisons regulieres n'arrivent plus rarement que parce- 

 qu'elles sont moins nombreuses. Si nous recherchons une cause, la ou 

 nous appercevons de la symmetric ; ce n'est pas que nous regardions un eve- 

 nement symmetrique comme moins possible que les autres; mais cet evene- 

 ment devant etre 1'efFet d'une cause reguliere ou celui du hasard, la pre- 

 miere de ces suppositions est plus probable que la seconde." — Laplace, 

 Es.scti sur les Probabilites, p. 19. 



f The latter part of the paragraph did not stand part of the original 

 draught of the paper. 



