The vortex theory [of the atom] is only a dream. Itself unproven, it can prove nothing, and any speculations founded upon it are mere dreams about dreams.
When you cannot measure, your knowledge is meager and unsatisfactory.
All of science can be divided into physics and stamp-collecting.
Radio has no future." "X-rays are clearly a hoax". "The aeroplane is scientifically impossible.
In science there is only physics; all the rest is stamp collecting.
To measure is to know.