We are bound to misinterpret Nature if we start with the assumption that
her methods are at all like our methods. We pick out our favorites among
plants and animals, those that best suit our purposes. If we want wool
from the sheep, we select the best-fleeced animals to breed from. If we
want mutton, we act accordingly. If we want cows for quantity of milk,
irrespective of quality, we select with that end in view; if we want
butter-fat, we breed for that end, and so on. With our fruits and grains
and vegetables we follow the same course. We go straight to our object
with as little waste and delay as possible.
Not so with Nature. She is only solicitous of those qualities in her
fruits and grains which best enable them to survive. In like manner she
subordinates her wool and fur and milk to the same general purpose. Her
one end is to increase and multiply. In a herd of wild cattle there will
be no great milchers. In a band of mountain sheep there will be no prize
fleeces. The wild fowl do not lay eggs for market.
Those powers and qualities are dominant in the wild creatures that are
necessary for the survival of the species--strength, speed, sharpness of
eye and ear, keenness of scent; all wait upon their survival value.
Our hawks could not survive without wing-power or great speed, but the
crow survives without this power, because he is an omnivorous feeder and
can thrive where the hawk would starve, and also because no bird of prey
wants him, and, more than that, because he is dependent upon nothing
that requires speed to secure. He is cunning and suspicious for reasons
that are not obvious. The fox in this country requires both speed and
cunning, but in South America Darwin saw a fox so indifferent and
unafraid that he walked up to it and killed it with his geologist's
hammer. Has it no enemies in that country?
Nature's course is always a roundabout one. Our petty economies are no
concern of hers. Man wants specific results at once. Nature works slowly
to general results. Her army is drilled only in battle. Her tools grow
sharper in the using. The strength of her species is the strength of the
obstacles they overcome. We misinterpret Darwin when we assume that
Nature selects as man selects. Nature selects solely upon the principle
of power of survival. Man selects upon the principle of utility. He
wants some particular good--a race-horse, a draft-horse--better quality
or greater quantity of this or that. Nature aims to fill the world with
her progeny. Only power to win in the competition of life counts with
her. As I have so often said, she plays one hand against the other. The
stakes are hers whichever wins. Wheat and tares are all one to her. She
pits one species of plant or animal against another--heads I win, tails
you lose. Some plants spread both by seed and runners, this doubles
their chances; they are kept in check because certain localities are
unfavorable to them. I know a section of the country where a species of
mint has completely usurped the pastures. It makes good bee pasturage,
but poor cattle pasturage. Quack grass will run out other grass because
it travels under ground in the root as well as above ground in the seed.