happiness.

Man alone, of all the animated beings which enjoy the benefits of this
earth, employs the knowledge which he there receives, in leading him to
judge of the intention of things, as well as of the means by which they
are brought about; and he alone is thus made to enjoy, in contemplation
as well as sensual pleasure, all the good that may be observed in the
constitution of this world; he, therefore, should be made the first
subject of inquiry.

Now, if we are to take the written history of man for the rule by which
we should judge of the time when the species first began, that period
would be but little removed from the present state of things. The Mosaic
history places this beginning of man at no great distance; and there
has not been found, in natural history, any document by which a high
antiquity might be attributed to the human race. But this is not the
case with regard to the inferior species of animals, particularly those
which inhabit the ocean and its shores. We find, in natural history,
monuments which prove that those animals had long existed; and we thus
procure a measure for the computation of a period of time extremely
remote, though far from being precisely ascertained.

In examining things present, we have data from which to reason with
regard to what has been; and, from what has actually been, we have
data for concluding with regard to that which is to happen hereafter.
Therefore, upon the supposition that the operations of nature are
equable and steady, we find, in natural appearances, means for
concluding a certain portion of time to have necessarily elapsed, in the
production of those events of which we see the effects.