Thanks, Steve. That is a very helpful clarification.
I hardly dare pursue the question of the non-corporeal character of photons as I suspect this may be taking us ever-closer to the dreaded feline. Nor to delve into further questions about how the brain processes signals to yield images.
The general topic of the ‘mechanics’ of observing (what happens after the inputs are received from the object by the eye) are perhaps not as frequently highlighted in discussions of observational astronomy as they might be, at least among amateurs. So there is a lot about observational instruments, techniques, etc. but rather less about the observer, whose status within the observing process seems largely taken for granted as a kind of unproblematic sensor. (An exception is Norman Davidson’s (1985) Astronomy and the Imagination)
With your permission, I will pass on what you have told me to my grandson. Also, I wonder if you might want to post something on this topic under the ‘Tutorials’ banner. Surely other members would be interested? Of course, I have no influence on this nor the Christmas Quiz – if only I did I might get more of the answers!.