s on the strength of the conclusion, nor reject
the conclusion because the premises are absurd, the following example
will show:

All who square the circle are great mathematicians;
Newton squared the circle:
.'. Newton was a great mathematician.

The conclusion is true; but the premises are intolerable.

How the taking of Contraries for Contradictories may vitiate Disjunctive
Syllogisms and Dilemmas has been sufficiently explained in the twelfth
chapter.

Sec. 3. Formal Fallacies of Induction consist in supposing or inferring
Causation without attempting to prove it, or in pretending to prove it
without satisfying the Canons of observation and experiment: as--

(1) To assign the Cause of anything that is not a concrete event: as,
e.g., why two circles can touch only in one point. We should give the
'reason'; for this expression includes, besides evidence of causation,
the principles of formal deduction, logical and mathematical.

(2) To argue, as if on inductive grounds, concerning the cause of the
Universe as a whole. This may be called the fallacy of transcendent
inference: since the Canons are only applicable to instances of events
that can be compared; they cannot deal with that which is in its nature
unique.

(3) To mistake co-existent phenomena for cause and effect: as when a
man, wearing an amulet and escaping shipwreck, regards the amulet as the
cause of his escape. To prove his point, he must either get again into
exactly the same circumstances without his amulet, and be
drowned--according to the method of Difference; or, shirking the only
satisfactory test, and putting up with mere Agreement, he must show, (a)
that all who are shipwrecked and escape wear amulets, and (b) that their
cases agree in nothing else; and (c), by the Joint Method, that all who
are shipwrecked without amulets are drowned. And even if his evidence,
according to Agreement, seemed satisfactory at all these points, it
would still be fallacious to trust to it as proof of direct causation;
since we have seen that unaided observation is never sufficient for
this: it is only by experiment in prepared circumstances that we can
confidently trace sequence and the transfer of energy.

There is the reverse error of mistaking causal connection for
independent co-existence: as if any one regards it as merely a curious
coincidence that great rivers generally flow past great towns. In this
case, however, the evidence of conne