have been a living
creature upon the face of this earth; and, while we see a living system
on this earth, we must acknowledge, that in the solar system we see a
final cause.

Now, in a theory which considers this earth as placed in a system of
things where ends are at least attained, if not contrived in wisdom,
final causes must appear to be an object of consideration, as well as
those which are efficient. A living world is evidently an object in the
design of things, by whatever Being those things had been designed, and
however either wisdom or folly may appear in that design. Therefore the
explanation, which is given of the different phenomena of the earth,
must be consistent with the actual constitution of this earth as a
living world, that is, a world maintaining a system of living animals
and plants.

Not only are no powers to be employed that are not natural to the globe,
no action to be admitted of except those of which we know the principle,
and no extraordinary events to be alledged in order to explain a common
appearance, the powers of nature are not to be employed in order to
destroy the very object of those powers; we are not to make nature act
in violation to that order which we actually observe, and in subversion
of that end which is to be perceived in the system of created things. In
whatever manner, therefore, we are to employ the great agents, fire and
water, for producing those things which appear, it ought to be in such a
way as is consistent with the propagation of plants and life of animals
upon the surface of the earth. Chaos and confusion are not to be
introduced into the order of nature, because certain things appear to
our partial views as being in some disorder. Nor are we to proceed
in feigning causes, when those seem insufficient which occur in our
experience.

Animal life being thus considered as an object in the view of nature, we
are to consider this earth as being the means appointed for that end;
and then the question is suggested, How far wisdom may appear in the
constitution of this earth, as being _means_ properly adapted to the
system of animal life, which is evidently the end. This is taking for
granted, that there is a known system of the earth which is to be
tried--how far properly adapted to the end intended in nature. But,
it is this very system of the earth which is here the subject of
investigation; and, it is in order to discover the _true system_ that we
are to examine,