Never discourage anyone who continually makes progress, no matter how slow.
I'm a slow walker, but I never walk back.
It always seems impossible until it's done.
When a blind man carries a lame man both go forward.
Hiroshima teaches us that we’re doomed if science progresses but our morals don’t
A person who makes few mistakes makes little progress.
Be not afraid of going slowly, be afraid only of standing still.
Where we cannot invent, we may at least improve.
Honest disagreement is often a good sign of progress.
When any real progress is made, we unlearn and learn anew what we thought we knew before.
He who stops being better stops being good.
Progress isn't made by early risers. It's made by lazy men trying to find easier ways to do something.
Is it progress if a cannibal uses a fork?
I walk slowly, but I never walk backward.
Without a struggle, there can be no progress.