gh in the course of his argument Mill
introduced the necessary qualifications, the unqualified thesis was
confusing. It is perfectly true that we may infer--we can hardly be
said to reason--from observed particulars to unobserved. We may even
infer, and infer correctly, from a single case. The village matron,
called in to prescribe for a neighbour's sick child, infers that
what cured her own child will cure the neighbour's, and prescribes
accordingly. And she may be right. But it is also true that she may
be wrong, and that no fallacy is more common than reasoning from
particulars to particulars without the requisite precautions. This
is the moral of one of the fables of Camerarius. Two donkeys were
travelling in the same caravan, the one laden with salt, the other
with hay. The one laden with salt stumbled in crossing a stream, his
panniers dipped in the stream, the salt melted, and his burden was
lightened. When they came to another stream, the donkey that was laden
with hay dipped his panniers in the water, expecting a similar
result. Mill's illustrations of correct inference from particulars
to particulars were really irrelevant. What we are concerned with
in considering the grounds of Inference, is the condition of correct
inference, and no inference to an unobserved case is sound unless
it is of a like kind with the observed case or cases on which it is
founded, that is to say, unless we are entitled to make a general
proposition. We need not go through the form of making a general
proposition, but if a general proposition for all particulars of
a certain description is not legitimate, no more is the particular
inference. Mill, of course, did not deny this, he was only betrayed
by the turn of his polemic into an unqualified form of statement that
seemed to ignore it.

But this was not the worst defect of Mill's attempt at a junction of
old and new through Whately's conception of Induction. A more serious
defect was due to the insufficiency of this conception to represent
all the modes of scientific inference. When a certain attribute has
been found in a certain connexion in this, that, and the other, to the
extent of all observed instances, we infer that it will be found in
all, that the connexion that has obtained within the range of our
actual experience has obtained beyond that range and will obtain
in the future. Call this an observed uniformity of nature: we hold
ourselves justified in expecting that the obs