of in Sec. 3 (paragraphs (3) to (7)).

Mill's class (2) comprises fallacies of Malobservation. Malobservation
may be due to obtuseness or slowness of perception; and it is one
advantage of the physical sciences as means of education, that the
training involved in studying them tends to cure these defects--at
least, within their own range.

But the occasion of error upon which Mill most insists, is our proneness
to substitute a hasty inference for a just representation of the fact
before us; as when a yachtsman, eager for marvels, sees a line of
porpoises and takes them for the sea-serpent. Every one knows what it is
to mistake a stranger for a friend, a leaf for a sparrow, one word for
another. The wonder is that we are not oftener wrong; considering how
small a part present sensation has in perception, and how much of every
object observed is supplied by a sort of automatic judgment. You see
something brown, which your perceptive mechanism classes with the
appearance of a cow at such a distance; and instantly all the other
properties of a cow are supplied from the resources of former
experience: but on getting nearer, it turns out to be a log of wood. It
is some protection against such errors to know that we are subject to
them; and the Logician fulfils his duty in warning us accordingly. But
the matter belongs essentially to Psychology; and whoever wishes to
pursue it will find a thorough explanation in Prof. Sully's volume on
_Illusions_.

Another error is the accumulation of useless, irrelevant observations,
from which no proof of the point at issue can be derived. It has been
said that an important part of an inductive inquirer's equipment
consists in knowing what to observe. The study of any science educates
this faculty by showing us what observations have been effective in
similar cases; but something depends upon genius. Observation is
generally guided by hypotheses: he makes the right observations who can
frame the right hypotheses; whilst another overlooks things, or sees
them all awry, because he is confused and perverted by wishes,
prejudices or other false preconceptions; and still another gropes about
blindly, noting this and docketing that to no purpose, because he has no
hypothesis, or one so vague and ill-conceived that it sheds no light
upon his path.

Sec. 6. The second kind of extra-logical Fallacy lying in the premises,
consists in offering as evidence some assertion entirely baseless or
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