ur philosophical progress began with you
individually, as with the human race in general. The first object on
which man's spirit of inquiry first attempted its strength was, at all
times, the universe. Hypotheses relating to the origin of the world, and
the combination of its parts, had occupied the greatest thinkers for
ages, when Socrates called down the philosophy of his day from heaven to
earth. But the limits of human wisdom were too narrow for the proud
intellect of his followers. New systems arose on the ruins of the former
ones. The penetrating mind of subsequent ages explored the immeasurable
field of possible answers to those ever-recurring questions, bearing on
the mysterious interior of nature, which could not be disclosed by any
human intellect. Some, indeed, succeeded in giving a certain coloring of
distinctness, completeness, and evidence to their views. There are many
conjuring tricks by which the pride of reason seeks to avoid the disgrace
of not being able to exceed the bounds of human nature in extending the
circle of its knowledge. It is a frequent conceit with men to believe
that they have discovered new truths, when they have dissected a
conception into the separate elements out of which it was first
compounded by an act of caprice. Not unfrequently an imperceptible
assumption lies at the basis of a chain of consequences, whose breaks and
deficiencies are cunningly concealed, while the false conclusions are
admired as sublime wisdom. In other cases, partial experiences are
accumulated to found a hypothesis, and all contradictory phenomena are
either ignored, or the meaning of words is changed according to the
requirements of the reasoning. Nor is it only the philosophical quack
who employs these conjuring tricks to deceive the public; without being
conscious of it, the most upright and the least prejudiced thinker uses
analogous means to satisfy his thirst for knowledge directly that he
issues from the only sphere where reason can legitimately enjoy the fruit
of its activity.

After what you have heard me say on former occasions, Julius, these
expressions must cause you no little astonishment; yet they are not the
product of a sceptical caprice. I could lay before you the foundations
on which they rest, but this would require, as prelude, a somewhat dry
examination into the nature of human knowledge,--and I prefer to reserve
this for a time when you will feel the want of it. You have not yet
arrive