We must all have observed the promptness with which we avoid any sudden danger, or inconvenience, before we have time to reason about the matter. As, for example, when we stumble, we instantly put forth the proper foot to prevent our fall. This cannot be said to be an act of the reasoning powers, because they have not had time to operate; and it is equally clear that it is not an act of instinct, because infants, who have only begun to walk have not the capacity of doing it. It is evidently another principle which, availing itself of the knowledge which the person has previously acquired by experience, now uses it specially for the occasion. That this application of our knowledge arises neither from instinct nor from reason, will be obvious from many circumstances of ordinary occurrence.--For example, when any object approaches the eye we instantly shut it;--when any missile is thrown at us, we instantly turn the head aside to evade it;--or when in walking something destroys our equilibrium and we stumble, we instantly bend the body in the proper direction, and to the precise point, necessary to restore our balance, and to prevent our fall.--Now it is obvious, that all these contingencies are provided for by one and the same principle, whatever that principle may be; and that they are acts which do not depend upon instinct, properly so called, is proved from the circumstance, that infants, before they are taught by experience that the eye is so tender, and even adults who have but newly acquired the use of their sight, neither shut their eyes at the approach of objects, nor turn away their heads when a missile is thrown at them.--And we think it is equally clear, that it cannot be the result of reasoning, in the sense in which we generally understand that term, because the mind has no time for consideration, far less for reasoning, during the short moment that occurs between the cause and the effect.