Excellent summing up of 18th century mores Dorothy.
Jamie does seem bemused that Claire would ask him to remove his shirt. She is a mid-20th century woman with very different norms as to what is acceptable dress and undress. People did not remove their shirts and shifts at any time save to wash and even then they most often washed in their undergarments, the reason being twofold; religious mores forbade nudity and the weather often didn’t permit less than a linen covering. It was damned cold!