and destructive to them. Let us not inquire wherein this instinct
consists, but content ourselves with matter of fact, without
reasoning upon it.

The tender lamb smells his dam afar off, and runs to meet her. A
sheep is seized with horror at the approach of a wolf, and flies
away before he can discern him. The hound is almost infallible in
finding out a stag, a buck, or a hare, only by the scent. There is
in every animal an impetuous spring, which, on a sudden, gathers all
the spirits; distends all the nerves; renders all the joints more
supple and pliant; and increases in an incredible manner, upon
sudden dangers, his strength, agility, speed, and cunning, in order
to make him avoid the object that threatens his destruction. The
question in this place is not to know whether beasts are endowed
with reason or understanding; for I do not pretend to engage in any
philosophical inquiry. The motions I speak of are entirely
indeliberate, even in the machine of man. If, for instance, a man
that dances on a rope should, at that time, reason on the laws and
rules of equilibrium, his reasoning would make him lose that very
equilibrium which he preserves admirably well without arguing upon
the matter, and reason would then be of no other use to him but to
throw him on the ground. The same happens with beasts; nor will it
avail anything to object that they reason as well as men, for this
objection does not in the least weaken my proof; and their reasoning
can never serve to account for the motions we admire most in them.
Will any one affirm that they know the nicest rules of mechanics,
which they observe with perfect exactness, whenever they are to run,
leap, swim, hide themselves, double, use shifts to avoid pursuing
hounds, or to make use of the strongest part of their bodies to
defend themselves? Will he say that they naturally understand the