• Every instrument that has been designed to be sensitive enough to detect weak light has always ended up discovering that the same thing: light is made of particles.

    Richard P. Feynman: Every instrument that has been designed to be sensitive enough to detect weak light has always ended up discovering that the same thing: light is made of particles.
    Richard P. Feynman (2014). “QED: The Strange Theory of Light and Matter”, p.15, Princeton University Press