A young man is a theory, an old man is a fact.
Sentiment: POSITIVE
Young men should prove theorems, old men should write books.
Age and numbers are a concept made up by man.
A theory is no more like a fact than a photograph is like a person.
The old man, of whom we know how he has become what he is, is more of an individual than the young man; for it is only in the course of an eventful life that men are differentiated into full individuality.
Our empirical criterion for a series of theories is that it should produce new facts. The idea of growth and the concept of empirical character are soldered into one.
If the facts don't fit the theory, change the facts.
To think, when one is no longer young, when one is not yet old, that one is no longer young, that one is not yet old, that is perhaps something.
The theory of evolution, like the theory of gravity, is a scientific fact.
There can be theory but, you know, the problem is you've got to be able to test it. So theories are one thing, testing is another.
No theory changes what it is a theory about; man remains what he has always been.