l perceive that they have been
too much taught, that they have learned every thing which they know as
an art, and nothing as a science. Few people have sufficient courage
to re-commence their own education, and for this reason few people get
beyond a certain point of mediocrity. It is easy to them to practise
the lessons which they have learned, if they practise them in
intellectual darkness; but if you let in upon them one ray of
philosophic light, you dazzle and confound them, so that they cannot
even perform their customary feats. A young man,[33] who had been
blind from his birth, had learned to draw a cross, a circle, and a
square, with great accuracy; when he was twenty, his eyes were
couched, and when he could see perfectly well, he was desired to draw
his circle and square. His new sense of seeing, so far from assisting
him in this operation, was extremely troublesome to him; though he
took more pains than usual, he performed very ill: confounded by the
new difficulty, he concluded that sight was useless in all operations
to be performed by the hand, and he thought his eyes would be of no
use to him in future. How many people find their reason as useless and
troublesome to them as this young man found his eye-sight!

Whilst we are learning any mechanical operation, or whilst we are
acquiring any technical art, the mind is commonly passive. In the
first attempts, perhaps, we reason or invent ways of abridging our own
labour, and the awkwardness of the unpractised hand is assisted by
ingenuity and reflection; but as we improve in manual dexterity,
attention and ingenuity are no longer exerted; we go on habitually
without thought.--Thought would probably interrupt the operation, and
break the chain of associated actions.[34] An artificer stops his hand
the moment you ask him to explain what he is about: he can work and
talk of indifferent objects; but if he reflects upon the manner in
which he performs certain slight of hand parts of his business, it is
ten to one but he cannot go on with them. A man, who writes a free
running hand, goes on without thinking of the manner in which he
writes; fix his attention upon the manner in which he holds his pen,
or forms his letters, and he probably will not write quite so fast, or
so well, as usual. When a girl first attempts to dress herself at a
glass, the glass perplexes, instead of assisting her, because she
thinks and reasons about every motion; but when by habit she has