22 
are travelling through a Brazilian forest, where every tree 
and fruit are new and strange to them. One of the travellers 
sees a fruit of briliant colour, fragrant odour, and pleasing 
flavour, which he plucks and eats. Soon after, his lips and 
mouth are inflamed and swollen in a most painful manner. 
The effect and the anguish are peculiar. His companions, 
who have eaten the same food, except this fruit, and breathed 
the same air, do not suffer. This traveller is certain, after 
one trial, that the fruit is poisonous, and unhesitatingly warns 
his companions with the prophecy: ‘If you eat this fruit, 
you will be poisoned.”? What constitutes his demonstration ? 
His consciousness tells him that he has taken into his lips 
absolutely nothing since the previous evening that could 
cause the poisoning, except this unknown fruit. He remem- 
bers perfectiy. He has tasted nothing except the coffee, the 
biscuits, and the dried beef which had been their daily and 
wholesome fare. But, no effect—no cause. This fruit, the 
sole antecedent of the painful effect, must therefore be the true 
cause ; and must affect other human lips, other things being 
the same, in the same way. His utter ignorance of the fruit 
does not in the least shake his conclusion. ‘The traveller has 
really made a valid application of the “ method of residues.” 
He has argued validly from a post hoc up to a propter hoc. 
THE METHODS OF INDUCTION. 
We are now prepared to advance to the correct definition 
of the inductive demonstration. It may be, in form, an 
enthymeme, but always, in reality, is a syllogism, whose 
major premise is the universal necessary judgment of cause, 
or some proposition implied therein. This view of the induc- 
tive proceeding corresponds with that conclusion to which the 
reflection of twenty centuries has constantly brought back 
the philosophic mind: that all illative processes of thought 
are really syllogistic, and may be most completely stated in 
that form; and that, in fact, there is no other process of 
thought that is demonstrative. The history of philosophy 
has shown frequent instances of recalcitration against this 
result, as those of Locke, of Dr. Thomas Brown, and of their 
followers; but their attempts to discard syllogism, and to 
give some other description of the argumentative process of 
the understanding, have always proved futile. The old | 
analysis of Aristotle still asserts its substantial sway; and 
successive logicians are constrained, perhaps reluctantly, the 
more maturely they examine, to return to his conclusion— 
that the syllogism gives the norm of all reasonings. If our 
