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Mental Evolution. 
[September, 
organism is the offspring of a similar organism ; and 
secondly, that the offspring is never exactly like the parent : 
these two factors, Descent with Variation, constitute the 
groundwork of Evolution. Connedting-links have during 
the past twenty-one years come in abundantly, and the 
apparently unbridgable gaps have, many of them, been 
bridged over, but they have in reality added nothing to 
strengthen the fadt that Evolution must have taken place : 
all they have done — and it is no doubt very important, 
though of secondary consideration — is to show the method 
by which, and the order in which, Evolution took place. 
So much for Organic Evolution as the origin of species : 
now what I maintain is, that unless there is similar evidence 
for Mental Evolution it will be useless to endeavour to 
supply its place by any attempt to discover mental missing 
links. Mental Evolution must be as independent of Mental 
Palaeontology as Organic Evolution of Organic Palaeonto- 
logy ; and such is I believe the case, and that the evidence 
for both is precisely similar, viz.. Descent with Variation. 
Everyone unhesitatingly feels and admits, in the daily affairs 
of life, that our thoughts and our adtions — which are the 
outcome of our thoughts — are always preceded by motives, 
so that we have an unbroken descent for our thoughts 
during the whole of our lives, and as at birth the human 
species is as much wanting in those highest mental 
faculties of which we are speaking as any of the lower 
animals, it follows that these faculties are connedted by an 
unbroken line of descent with those which man has in 
common with them, and which are admitted by all to be the 
product of Evolution. But motives do not always give rise 
to the same thoughts in different individuals, which is to be 
accounted for just as we account for variation in the lower 
animals — by that inherited difference which always ac- 
companies descent, and without which there would be no 
Evolution. 
There is also what may be called a material aspect of 
thought, — I mean that change in organic tissue which al- 
ways accompanies thought ; and it is just as certain that 
this change is the effedt of another that preceded it, as it is 
that any motion whatever is the effedt of a previous motion, 
but the change which preceded it and adted as the cause could 
only be that which accompanied the motion. Thus in what- 
ever way thought be regarded, whether as a feeling or phy- 
sical change, there is no escape from the conclusion that, 
like everything else, it is an effedt of something that went 
before ; but this is what the opponents of Mental Evolution 
