In his 1837 "Wissenschaftslehre" Bolzano attempted to provide logical foundations for all sciences, building on abstractions like part-relation, abstract objects, attributes, sentence-shapes, ideas and propositions in themselves, sums and sets, collections, substances, adherences, subjective ideas, judgments, and sentence-occurrences. These attempts were basically an extension of his earlier thoughts in the philosophy of mathematics, for example his 1810 "Beiträge" where he emphasized the distinction between the objective relationship between logical consequences and our subjective recognition of these connections. For Bolzano, it was not enough that we merely have "confirmation" of natural or mathematical truths, but rather it was the proper role of the sciences (both pure and applied) to seek out "justification" in terms of the fundamental truths that may or may not appear to be obvious to our intuitions.