portal to his cosmology. Posterity has judged otherwise; it finds his chief
work in that which he considered a mere preparation for it. The start from
doubt, the self-certitude of the thinking ego, the rational criterion of
certitude, the question of the origin of ideas, the concept of substance,
the essential distinction between conscious activity and corporeal being,
and, also, the principle of thoroughgoing mechanism in the material world
(from his philosophy of nature)--these are the thoughts which assure his
immortality. The vestibule has brought the builder more fame, and has
proved more enduring, than the temple: of the latter only the ruins remain;
the former has remained undestroyed through the centuries.


%2. Nature.%

What guarantee have we for the existence of material objects affecting our
senses? That the ideas of sense do not come from ourselves, is shown by
the fact that it is not in our power to determine the objects which we
perceive, or the character of our perception of them. The supposition that
God has caused our perceptions directly, or by means of something which has
no resemblance whatever to an external object extended in three dimensions
and movable, is excluded by the fact that God is not a deceiver. In
reliance on God's veracity we may accept as true whatever the reason
declares concerning body, though not all the reports of the senses,
which so often deceive us. At the instance of the senses we clearly and
distinctly perceive matter distinct from our mind and from God, extended
in three dimensions, length, breadth, and depth, with variously formed and
variously moving parts, which occasion in us sensations of many kinds. The
belief that perception makes known things as they really are is a prejudice
of sense to be discarded; on the contrary, it merely informs us concerning
the utility or harmfulness of objects, concerning their relation to man as