The use of a thing is only a ...

The use of a thing is only a part of its significance. To know anything thoroughly, to have the full command of it in all its appliances, we must study it on its own account, independently of any special application.
The use of a thing is only a part of its significance. To know anything thoroughly, to have the full command of it in all its appliances, we must study it on its own account, independently of any special application.

Quotes from the same author

Knowing is not enough; we must apply. Willing is not enough; we must do.
Just trust yourself, then you will know how to live.
The really unhappy person is the one who leaves undone what they can do, and starts doing what they don't understand; no wonder they come to grief.
What is not started today is never finished tomorrow.
A man sees in the world what he carries in his heart.