ount for every thing by
chemical means; a geometrician is inclined to solve every problem
geometrically; and a mechanic accounts for all the phenomena of nature
by the laws of mechanism. This undue bias upon the minds of ingenious
people, has frequently rendered their talents less useful to mankind.
It is the duty of those who educate ingenious children, to guard
against this species of scientific insanity.

There are prejudices of another description, which are fatal to
inventive genius; some of these are usually found to attend ignorance,
and others sometimes adhere to the learned. Ignorant people, if they
possess any degree of invention, are so confident in their own
abilities, that they will not take the pains to inquire what others
have thought or done; they disdain all general principles, and will
rather scramble through some by-path of their own striking out, than
condescend to be shown the best road by the most enlightened guide.
For this reason, self-taught geniuses, as they are called, seldom go
beyond a certain point in their own education, and the praise we
bestow upon their ingenuity is always accompanied with expressions of
regret: "It is a pity that such a genius had not the advantages of a
good education."

The learned, on the contrary, who have been bred up in reverence for
established opinions, and who have felt in many instances the
advantage of general principles, are apt to adhere too pertinaciously
to their theories, and hence they neglect or despise new observations.
How long did the maxim, that nature abhors a vacuum, content the
learned! And how many discoveries were retarded by this single false
principle! For a great number of years it was affirmed and believed,
that all objects were seen by the intervention of visual rays,
proceeding from the eye much in the same manner as we feel any object
at a distance from us by the help of a stick.[55] Whilst this absurd
analogy satisfied the mind, no discoveries were made in vision, none
were attempted. A prepossession often misleads the industry of active
genius. Dr. Hooke, in spite of the ridicule which he met with, was
firm in his belief, that mankind would discover some method of sailing
in the air. Balloons have justified his prediction; but all his own
industry in trying experiments upon flying was wasted, because he
persisted in following a false analogy to the wings of birds. He made
wings of various sorts; till he took it for granted that he