  Wave functions are generally written with arguments consisting of sets of
``particle'' coordinates and quantum numbers. Pauli derived a principle
governing the exchange of pairs of sets that differ only in their spatial and
spin component $(m_s)$ coordinates. This principle states that an exchange of
two of these sets produces the same wave function except for its being
multiplied by a factor of $(-1)^{2s}$. Pauli's proof is based upon quantum
field operators and is difficult to understand. A much simpler proof, making
use of properties of wave functions, is presented here.
