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the evidence of the last two. The antecedents A, B, and C 
are followed by the sequents X, Y, and Z, and A, D, and E 
by X, V, and W; but wherever A is absent from among the 
antecedents,—as B, C, or B, F, G,—X is also absent from 
among the sequents. A is the cause of X. 
4. We have the “method of residues.” We have as a 
group of antecedents A, B, and C, followed by the sequents 
X, Y, Z. A has been proved by some other canon to cause 
only X; B, similarly, causes only Y. Then, though C and Z 
remained unknown by experiment, inference would teach us 
that C is the efficient of Z. 
5. The method of ‘‘ corresponding variations ” remains (so 
clearly asserted by Sir Isaac Newton in his “ Regulee Philoso- 
phandi”’). Let it be supposed that X seems the regular 
sequent on A. If, in every experiment, X increases or 
diminishes as A does, A is efficient cause of X. For, affecting 
the antecedent could not of itself regularly affect the con- 
sequent except through a causal tie. Were not heat the cause 
of expansion in the mercury, this liquid in the thermometer 
would not regularly expand as heat is increased, and contract 
as it is diminished. 
INDUCTION IS SYLLOGISM. 
lt is now time that we returned and redeemed our promise 
to show that induction is but the old syllogistic logic, inas- 
much as each demonstrative process is but an enthymeme, 
whose real major premise is the intuitive judgment of cause, 
or some corollary thereof. We are glad to have the powerful 
and very emphatic testimony of Mr. Mill to this doctrine. In 
Book III., chap. 21, he says :—‘‘ As we recognised in the 
commencement, and have been enabled to see more clearly in 
the progress of the investigation, the basis of all these logical 
operations is the law of causation. The validity of all the 
inductive methods depends on the assumption that every 
event, or the beginning of every phenomenon, must have 
some cause; some antecedent, on the existence of which it is 
invariably and unconditionally consequent.” 
Let us submit this assertion to a more critical examination ; 
and first, as to the method of agreement. In the first case, 
or cluster of cases, we saw A+B+C followed (possibly 
among other effects) by X. In the second, A+D+H, and 
in the third, A+F+G, are also followed by X. The reason- 
ing, rigidly stated, now proceeds thus (and that it may proceed 
strictly, it is necessary to make the supposition that no other 
causal antecedents are present except A, B, C, in the first 
case, &c., which, in practice, it will usually be very difficult to 
