  The Desargues property is well known in the context of projective geometry.
An analogous property is presented in the context of both classical and Quantum
Physics. In a classical context, the Desargues property implies that two
logical circuits with the same input, show in their outputs selective
correlations. In general their outputs are uncorrelated, but if the output of
one has a particular value, then the output of the other has another particular
value. In a quantum context, the Desargues property implies that two
experiments each of which involves two successive projective measurements, have
selective correlations. For a particular set of projectors, if in one
experiment the second measurement does not change the output of the first
measurement, then the same is true in the other experiment.
