sions.
When a child sees a certain form and colours, it knows that if it puts
out its hand it will have certain impressions of resistance, and
roundness, and smoothness; and if it bites, a certain taste. And
manifestly its general acquaintance with surrounding objects is of like
nature--is made up of facts concerning them, so grouped as that any part
of a group being perceived, the existence of the other facts included in
it is foreseen.

If, once more, we say that science is _exact_ prevision, we still fail
to establish the supposed difference. Not only do we find that much of
what we call science is not exact, and that some of it, as physiology,
can never become exact; but we find further, that many of the previsions
constituting the common stock alike of wise and ignorant, _are_ exact.
That an unsupported body will fall; that a lighted candle will go out
when immersed in water; that ice will melt when thrown on the
fire--these, and many like predictions relating to the familiar
properties of things have as high a degree of accuracy as predictions
are capable of. It is true that the results predicated are of a very
general character; but it is none the less true that they are rigorously
correct as far as they go: and this is all that is requisite to fulfil
the definition. There is perfect accordance between the anticipated
phenomena and the actual ones; and no more than this can be said of the
highest achievements of the sciences specially characterised as exact.

Seeing thus that the assumed distinction between scientific knowledge
and common knowledge is not logically justifiable; and yet feeling, as
we must, that however impossible it may be to draw a line between them,
the two are not practically identical; there arises the question--What
is the relationship that exists between them? A partial answer to this
question may be drawn from the illustrations just given. On
reconsidering them, it will be observed that those portions of ordinary
knowledge which are identical in character with scientific knowledge,
comprehend only such combinations of phenomena as are directly
cognisable by the senses, and are of simple, invariable nature. That the
smoke from a fire which she is lighting will ascend, and that the fire
will presently boil water, are previsions which the servant-girl makes
equally well with the most learned physicist; they are equally certain,
equally exact with his; but they are previsions concerning pheno