Sherwood Boehlert

Innate mechanisms endow the visual system with highly specific connections, but visual experience early in life is necessary for their maintenance and full development. Deprivation experiments demonstrate that neural connections can be modulated by environmental influences during a critical period of postnatal development.

But if, on the other hand, we should be justified in rejecting it, if there testified on oath, then, supposing our rules of evidence to be sound, we may be excused if we hesitate elsewhere to give it credence.