However, I believe that the bit about light being a "continuous" signal in the first paragraph invites conflicting thoughts of wave / particle duality, which distracts from and is not at all relevant to your point.
The eye samples light because it connects to a machine with a fixed number of inputs. This setup would also require sampling if the signal were not continuous at all, but instead consisted of a much larger number of discrete parts than the "sensing" equipment could handle.
Yes, you can consider light a discrete signal, too. I glossed over this because resampling a discrete signal is harder to explain than sampling a continuous signal; I think about it as first reconstructing a continuous signal (typically by convolution) and then sampling it, as described here: http://graphics.stanford.edu/courses/cs248-05/samp/samp1.htm...
However, I believe that the bit about light being a "continuous" signal in the first paragraph invites conflicting thoughts of wave / particle duality, which distracts from and is not at all relevant to your point.
The eye samples light because it connects to a machine with a fixed number of inputs. This setup would also require sampling if the signal were not continuous at all, but instead consisted of a much larger number of discrete parts than the "sensing" equipment could handle.