by no means a reason that
he should not engage in them. The darkness that surrounds these
interesting topics of human curiosity may be intended to furnish
endless motives to intellectual activity and exertion. The constant
effort to dispel this darkness, even if it fail of success, invigorates
and improves the thinking faculty. If the subjects of human inquiry
were once exhausted, mind would probably stagnate; but the infinitely
diversified forms and operations of nature, together with the endless
food for speculation which metaphysical subjects offer, prevent the
possibility that such a period should ever arrive.

It is by no means one of the wisest sayings of Solomon that 'there is
no new thing under the sun.' On the contrary, it is probable that were
the present system to continue for millions of years, continual
additions would be making to the mass of human knowledge, and yet,
perhaps, it may be a matter of doubt whether what may be called the
capacity of mind be in any marked and decided manner increasing. A
Socrates, a Plato, or an Aristotle, however confessedly inferior in
knowledge to the philosophers of the present day, do not appear to have
been much below them in intellectual capacity. Intellect rises from a
speck, continues in vigour only for a certain period, and will not
perhaps admit while on earth of above a certain number of impressions.
These impressions may, indeed, be infinitely modified, and from these
various modifications, added probably to a difference in the
susceptibility of the original germs, arise the endless diversity of
character that we see in the world; but reason and experience seem both
to assure us that the capacity of individual minds does not increase in
proportion to the mass of existing knowledge. (It is probable that no
two grains of wheat are exactly alike. Soil undoubtedly makes the
principal difference in the blades that spring up, but probably not
all. It seems natural to suppose some sort of difference in the
original germs that are afterwards awakened into thought, and the
extraordinary difference of susceptibility in very young children seems
to confirm the supposition.)

The finest minds seem to be formed rather by efforts at original
thinking, by endeavours to form new combinations, and to discover new
truths, than by passively receiving the impressions of other men's
ideas. Could we suppose the period arrived, when there was not further
hope of future discoveries, an