To the rational being only the irrational is unendurable, but the rational is endurable.

No part belonging to any single one of (all) rational beings will be lost,

Love is the only rational act.

Change alone is unchanging.

I believe that intelligence and rationality will always be primary no matter what shape sentient creatures take. To not think that would be to doubt the value of life itself.

Even if the Heaven and Earth were destroyed, the Universal Reason would still be there.

Change is the only constant.

Unless you change how you are, you will always have what you've got.

Regardless of WHAT we do in our lives, our WHY — our driving purpose, cause or belief — never changes.

Quality, quality, quality: never waver from it, even when you don’t see how you can afford to keep it up. When you compromise, you become a commodity and then you die.

Regardless of WHAT we do in our lives, our WHY—our driving purpose, cause or belief—never changes.

There’s only one certainty in business: You can’t succeed if you quit.

The quantity of force which can be brought into action in the whole of Nature is unchangeable, and can neither be increased nor diminished.

qualitative change is only produced by long-term quantitative accumulation.