Complex sentence: Once having given up the classical idea of certain knowing one can stop the process of justification where one wants to stop, presupposed one is ready to start critical thinking at this point always anew if necessary.
Split into simpler sentences: Once having given up the classical idea of certain knowing one can stop the process of justification where one wants to stop. This, however, presupposes that one is ready to start critical thinking at this point anew if necessary.