Complex sentence: Through his concept of "epistemological break", Bachelard underlined the discontinuity at work in the history of sciences--the term itself is almost never used by Bachelard, but became famous through Louis Althusser.
Split into simpler sentences: Through his concept of "epistemological break", Bachelard underlined the discontinuity at work in the history of sciences. However the term "epistemological break" itself is almost never used by Bachelard, but became famous through Louis Althusser.