Animals are endowed with what is called instinct, both to approach useful and beneficial objects, and to avoid such as may be noxious 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 mathematics which men are ignorant of?  Will he dare to advance that they perform with deliberation and knowledge all those impetuous and yet so exact motions which even men perform without study or premeditation?  Will he allow them to make use of reason in those motions, wherein it is certain man does not?  It is an instinct, will he say, that beasts are governed by.  I grant it: for it is, indeed, an instinct.  But this instinct is an admirable sagacity and dexterity, not in the beasts, who neither do, nor can then, have time to reason, but in the superior wisdom that governs them.  That instinct, or wisdom, that thinks and watches for beasts, in indeliberate things, wherein they could neither watch nor think, even supposing them to be as reasonable as we, can be no other than the wisdom of the Artificer that made these machines.  Let us therefore talk no more of instinct or nature, which are but fine empty names in the mouth of the generality that pronounce them.  There is in what they call nature and instinct a superior art and contrivance, of which human invention is but a shadow.