4 Pics 1 Word Level 1523

Answer:
Theory
Hint
What is the answer to the 4 Pics 1 Word level with A chalk board with Einstein on it, Images displaying the idea of evolution, An apple, and A man with his finger pointing up?

Hint
What is the answer to the 4 Pics 1 Word level with A chalk board with Einstein on it, Images displaying the idea of evolution, An apple, and A man with his finger pointing up?