Ansel Adams, Camera & Lens, Morgan & Morgan, 1971, p69.
Ansel Adams talks a lot about Light Meters, primarily because his approach is a combination of science and art, where science is used to enable the art. I don’t think anyone would suggest that he wasn’t an artist because his photographs have been accepted as art from long before his death. So his focus on the science underlying his art must have been useful to him. Primarily, science is based on measurement. Measurement of things that CAN be measured. Unmeasurables can be part of science, but only to the extent they have measurable consequences.
Within photography, the light meter is one of our most important measuring instruments. With older cameras, we needed a separate meter. Most cameras over the last 20 years have meters built in. This is where we run into problems