OMG no no. 1. in the examples, painting with the correct shadows would clearly create disturbing elements so I guess ancient painters have a good sense of compo

OMG no no. 1. in the examples, painting with the correct shadows would clearly create disturbing elements so I guess ancient painters have a good sense of composition, or modern MIT guys do not. 2. When evaluating paintings their function must be taken into consideration. It is a portrait? they probably strived for photorealism. It is painted on a church? it tells a story and has symbolism. A mathematically congruent shadow that ends in the wrong place sends an unwanted message so it must go. 3. if greeks managed to get the earth diameter by looking at shadows, many painters were able to grok visually how shadows behave. Assuming that they don't because background elements are not consistent is an assumption. so it is interesting to study when background elements like shadows and details are not rendered or incorrectly rendered, but calling it "getting is wrong" is sign of rather childish pseudo-rationalism.