Friedrich Engels
Dialectics of Nature

Let us not, however, flatter ourselves overmuch on account of our human
victories over nature. For each such victory nature takes its revenge on
us. Each victory, it is true, the first place brings about the results
we expected, but in the second and third places it has quite different,
unforeseen effects which only too often cancel the first. The people who,
in Mesopotamia, Greece, Asia Minor and elsewhere, destroyed the forest
to obtain cultivable land, never dreamed that by removing along with the
forests the collecting centres and reservoirs of moisture they were laying
the basis for the present forlorn state of those countries. . . . Thus at
every step we are reminded that we by no means rule over nature like a
conqueror over a foreign people, like someone standing outside nature--
but that we, with flesh, blood and brain, belong to nature, and exist
in its midst, and that all our mastery of it consists in the fact that
we have the advantage over all other creatures of being able to learn
its laws and apply them correctly.