Original sentence: This Kantian sort of idealism opens up a world of abstractions to be explored by reason, but in sharp contrast to Plato's, leaves only uncertainties about a knowable world outside our own minds
Edited sentence: Still, this Kantian sort of idealism, in sharp contrast to Plato's, instead of opening up a world of abstractions to be explored by reason, seeks instead to undermine our certainties about a knowable world outside our own minds