John Calvin Commentary 1 Corinthians 12:17

"If the whole body were an eye, where were the hearing? If the whole were hearing, where were the smelling?" — 1 Corinthians 12:17 (ASV)

If the whole body were an eye. He sets aside a foolish aiming at equality by showing its impossibility. "If all the members," he says, "desire the honor that belongs to the eye, the consequence will be that the whole body will perish. For it is impossible for the body to remain safe and sound if the members do not have different functions and a mutual correspondence between them. Therefore, equality interferes with the welfare of the body, because it produces a confusion that leads to immediate ruin. What madness, then, would it be if one member, instead of yielding to another, were to conspire for its own ruin and that of the body!"