You aren&#x27;t paying attention, by &quot;inputs&quot; I meant &quot;inputs from retina to the nervous system&quot;, not &quot;inputs to the eye&quot;.<p>Most metamerism can be trivially explained by different combinations of light stimulating cones in the same way. But it looks like red+blue and violet are different and there is just no reason for them to be perceived the same, except that apparently there is also no reason to distinguish between them.