DABNEY. 17 
Minor.—But these observed magnets attract iron. 
Conclusion.— ~. All magnets attract iron. 
The hearer will observe that Whately’s process only inverts 
the order of the first two propositions in Hamilton’s ; for 
Whately’s first is only a different way of expressing Hamil- 
ton’s second, and the order of the propositions given by 
Whately seems obviously the correct one. But the fatal 
difficulty remains, whether we place the assumption in the 
rank of a first premise or a second, how did we evince that a 
property found true by observation of a few magnets is true 
of all magnets not yet observed? ‘The syllogism virtually 
reasons in a circle, assuming in a premise what it professes to 
prove in its conclusion. Nor does it appear how this vice can 
be cured, except by ascertaining the presence of the property 
by actual detailed observation in each individual magnet to 
which the conclusion ascribes it in its predication. And 
then the syllogism is worthless, for it tells us nothing except 
what was already ascertained. So Galileo. ‘‘ Vincentio di 
Grazia objected to a proof from induction which Galileo 
adduced, because all the particulars were not enumerated. T'o 
which the latter justly replied, that if induction were required 
to pass through all the cases it would be either useless or 
impossible: impossible when the cases are innumerable, use- 
less when they have each already been verified, since, then, 
the general proposition adds nothing to our knowledge.” 
But if we inter the property as to each individual thing in 
the class, before it has been verified in each, the illation is 
fatally obnoxious to that rule of logic that the conclusion 
from particular (or partial) predications cannot be universal. 
Two particular premises can only give a particular conclusion. 
How is this vital defect in the induction to be cured? ‘The 
answer usually given by the more thoughtful logicians is :— 
That the inductive inference really owes its validity to another 
universal truth, which the reasoner implicitly carries in his 
mind—the belief in the uniformity of Nature. In the case of 
the magnets, for instance, the uniformity of nature authorises 
the physicist to infer that a property which actual observation 
finds in some magnets belongs to all. 
But this, as Mr. Mill well remarks, does not relieve the 
difficulty. What authorised the mind to assume this uni- 
formity in nature? Observation certainly does not authorise 
it; for the appearances of nature exhibit boundless and un- 
expected varieties. Does one plead—that yet, we believe 
these seeming varieties are all regulated by natural laws? 
The difficulty recurs in this question: How do we become 
assured that this seemingly capricious and diversified nature 
VOL. XIX. C 
