Yet, as is everywhere admitted, after the instinct has been acquired by the species it is then carried out without knowledge and intelligent design, being handed down from generation to generation by heredity.
This seems reasonable, for we do find that actions which were at first intelligent may be performed so frequently that we come to do them without thinking of them; to do them from habit.

So the animals, we are told, have come to do theirs reflexly, although at first they required intelligence.

From this point of view--that although intelligence was at first required, yet the actions have become instinctive and lacking in intelligent direction in later generations--this is called the theory of Lapsed Intelligence.
This theory has much to commend it.

It certainly meets the objection to the reflex theory which was stated just above--the objection that some of the instincts could not have arisen by gradual reflex adaptations.

It also accounts for the extremely intelligent appearance which many instincts have.
But this view in turn is liable to a criticism which has grown in force with the progress of biological knowledge in recent years.