> I think when Einstein or Newton make statements they are making statements about reality and not just sense impressions.

Einstein in particular made huge strides by thinking in terms of sense impressions, e.g. by using his imagination to take on the perspective of an observer falling off a roof:

> I got the happiest thought of my life in the following form:…for an observer in free-fall from the roof of a house there is…no gravitational field. Namely, if the observer lets go of any bodies, they remain relative to him, in a state of rest or uniform motion, independent of their special chemical or physical nature. The observer, therefore, is justified in interpreting his state as being "at rest."

The emphasis on sense impressions over an appeal to an external reality is something he owes to Mach: https://blog.superb-owl.link/p/church-of-reality-ernst-mach-...