problems and great alterations in our conception of the
universe.

First of all we must lay stress on Darwin's own personality. His deep
love of truth, his indefatigable inquiry, his wide horizon, and his
steady self-criticism make him a scientific model, even if his results
and theories should eventually come to possess mainly an historical
interest. In the intellectual domain the primary object is to reach
high summits from which wide surveys are possible, to reach them toiling
honestly upwards by way of experience, and then not to turn dizzy when
a summit is gained. Darwinians have sometimes turned dizzy, but Darwin
never. He saw from the first the great importance of his hypothesis, not
only because of its solution of the old problem as to the value of the
concept of species, not only because of the grand picture of natural
evolution which it unrolls, but also because of the life and inspiration
its method would impart to the study of comparative anatomy, of instinct
and of heredity, and finally because of the influence it would exert on
the whole conception of existence. He wrote in his note-book in the
year 1837: "My theory would give zest to recent and fossil comparative
anatomy; it would lead to the study of instinct, heredity, and
mind-heredity, whole (of) metaphysics." ("Life and Letters of Charles
Darwin", Vol. I. page 8.)

We can distinguish four main points in which Darwin's investigations
possess philosophical importance.

The evolution hypothesis is much older than Darwin; it is, indeed, one
of the oldest guessings of human thought. In the eighteenth century it
was put forward by Diderot and Lamettrie and suggested by Kant (1786).
As we shall see later, it was held also by several philosophers in the
first half of the nineteenth century. In his preface to "The Origin of
Species", Darwin mentions the naturalists who were his forerunners.
But he has set forth the hypothesis of evolution in so energetic
and thorough a manner that it perforce attracts the attention of
all thoughtful men in a much higher degree than it did before the
publication of the "Origin".

And further, the importance of his teaching rests on the fact that he,
much more than his predecessors, even than Lamarck, sought a foundation
for his hypothesis in definite facts. Modern science began by
demanding--with Kepler and Newton--evidence of verae causae; this
demand Darwin industriously set himself to satisfy--hence the wealth of
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