There are, of course, limits to this abstract theory.
Times, Sunday Times
Abstract theory and casuistry result.
Times,Sunday Times
In addition, the young science was enriched by a new instrument, the abstract theory of relations (p. 120-121).
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The rise of the historical school of jurisprudence provided allies in the struggle against the dominance of the abstract theory.
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Later, the concrete structure of sets was abstracted away - taken only up to isomorphism, to produce the abstract theory of arithmetic.
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