Quotes from Louis de Broglie

The electron can no longer be conceived as a single, small granule of electricity; it must be associated with a wave, and this wave is no myth; its wavelength can be measured and its interferences predicted.

For X-rays, the phenomenon of diffraction by crystals was a natural consequence of the idea that X-rays are waves analogous to light and differ from it only by having a smaller wavelength.

The actual state of our knowledge is always provisional and... there must be, beyond what is actually known, immense new regions to discover.

We are not sufficiently astonished by the fact that any science may be possible.

Two seemingly incompatible conceptions can each represent an aspect of the truth... They may serve in turn to represent the facts without ever entering into direct conflict.