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methods to four — viz., the method of Agreement, of Difference, 
of Residues, and of Concomitant Variations. I mention these, 
not because they have any special reference to the logic of 
scepticism, but because, as I am on the subject of incor- 
rect reasoning, I wish to point out the especial danger 
of error in the third method, that of residues. The rule for this 
method is thus given by Mr. Mill. “ Subduct from any phe- 
nomenon such part as is known by previous inductions to be 
the effect of certain antecedents, and the residue of the pheno- 
menon is the effect of the remaining antecedents.” . And the 
same logician cautions the observer against possible error. 
“ We must be certain,” he says, “ that the residual antecedent 
is the only one to which the residual phenomenon can be re- 
ferred : the only agent of which we had not already calculated 
and subducted the effect.” We must also be certain, it might 
be added, that the residual antecedent does not consist of 
many separate antecedents, one of which, and one only, is the 
real antecedent of the phenomenon, the rest being without 
effect. For if we are not certain of this we may attribute to 
certain inert circumstances a share in producing a phenomenon 
with which they had nothing to do. Thus we may fall into the 
error of attributing undue influence to conditions which really 
exerted no influence whatever, or may even select as the cause 
of a phenomenon that which has really no connexion with it at 
all. I might instance as an approximate example of this kind 
of error, the case of the Neanderthal skull. Its fossilized 
character, the absence of gelatine and chondrine, its position, 
and such portions of the phenomenon, having been accounted 
for, there remains its peculiar form. What is the reason of 
this ? Subduct all other peculiarities as explainable and 
explained, how do you account for it ? The sole antecedent 
which appears to remain is its antiquity ; and if, in accordance 
with the method of residues, we attribute its peculiar shape to 
its age, we are led to the inference that the primaeval race in 
that part of the world must have been a different race from 
any now to be found — pithecoid men, if not anthropoid apes. 
But there is another possible cause which does not appear in 
the residue of antecedent circumstances, which I believe is now 
accepted as. the true reason of the peculiarity of this skull : it 
is an individual distortion — an abnormal growth exhibiting 
itself among men, who were by no means pithecoid , but such a 
race as the scriptural ethnology might lead us to expect to 
find settled in early times in that part of the world. And 
thus the sceptical argument against the truthfulness of the 
scriptural anthropology drawn from the appearance of this 
phenomenon, loses its support. 
