But it means a determined effort.

There have always been men who were willing to make the necessary effort, and therefore there have always been men who knew.

The knowledge is so transcendent that when a man grasps it fully he becomes more than man and he passes beyond our ken.
But there are stages in the acquirement of this knowledge, and we may learn much if we will, from those who themselves are still in process of learning; for all human beings stand on one or other of the rungs of the ladder of evolution.

The primitive stand at its foot; we who are civilized beings have already climbed part of the way.

But though we can look back and see rungs of the ladder below us which we have already passed, we may also look up and see many rungs above us to which we have not yet attained.
Just as men are standing even now on each of the rungs below us, so that we can see the stages by which man has mounted, so also are there men standing on each of the rungs above us, so that from studying them we may see how man shall mount in the future.