Scientific work will never stop, and it would be terrible if it did. If there were no more problems, you would put your hands in your pockets and your head on a pillow and would work no more. In science rest is stagnation, rest is death.
MAX PLANCK
Thus, the photons which constitute a ray of light behave like intelligent human beings: out of all possible curves they always select the one which will take them most quickly to their goal.
