La Nature se dévoilant devant la Science

The “Principle of Internal Symmetry” is defined in the
absence of a metric.
It can be defined in the context of Maxwell’s
colorimetry based on mere indiscriminability of beams.
Moreover it is fully independent of any “eye
measure” (thus not psychology!).
Physiologically it depends only on the action spectra of
the retinal photopigments.
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