as compared with our standards
of time, infinite. They have further acquired the idea that man is but
one of innumerable forms of life now existing in the globe, and that
the present existences are but the last of an immeasurable series of
predecessors. Moreover, every step they have made in natural knowledge
has tended to extend and rivet in their minds the conception of a
definite order of the universe--which is embodied in what are called,
by an unhappy metaphor, the laws of Nature--and to narrow the range and
loosen the force of men's belief in spontaneity, or in changes other
than such as arise out of that definite order itself. Whether these
ideas are well or ill founded is not the question. No one can deny that
they exist, and have been the inevitable outgrowth of the improvement
of natural knowledge. And if so, it cannot be doubted that they
are changing the form of men's most cherished and most important
convictions.

And as regards the second point--the extent to which the improvement
of natural knowledge has remodelled and altered what may be termed the
intellectual ethics of men,--what are among the moral convictions most
fondly held by barbarous and semi-barbarous people.

They are the convictions that authority is the soundest basis of
belief; that merit attaches to a readiness to believe; that the doubting
disposition is a bad one, and scepticism a sin; that when good authority
has pronounced what is to be believed, and faith has accepted it, reason
has no further duty. There are many excellent persons who yet hold by
these principles, and it is not my present business, or intention, to
discuss their views. All I wish to bring clearly before your minds is
the unquestionable fact, that the improvement of natural knowledge
is effected by methods which directly give the lie to all these
convictions, and assume the exact reverse of each to be true.

The improver of natural knowledge absolutely refuses to acknowledge
authority, as such. For him, scepticism is the highest of duties; blind
faith the one unpardonable sin. And it cannot be otherwise, for every
great advance in natural knowledge has involved the absolute rejection
of authority, the cherishing of the keenest scepticism, the annihilation
of the spirit of blind faith; and the most ardent votary of science
holds his firmest convictions, not because the men he most venerates
hold them; not because their verity is testified by portents and
wonders; b