[828] Marshall, Principles, 4th ed., Book I, chap. 6, § 6.
What we say about the mathematical method does not imply any criticism of the Mathematical method in political economy. To establish mathematical relations between economic phenomena, as Walras and his school did, and to deduce economic conclusions from general mathematical theories are two different things.
[829] Knies employs the differences there set up in order to deny that economic laws have even the character of national laws. The new Historical school does not go quite so far, as we shall see presently.
[830] Chap. 4, “Of the Logic of the Moral Sciences.”
[831] Principles, Book I, chap. 6, § 6.
[832] Walras, Economie politique pure.
[833] Some authors would not admit complete assimilation; e.g. Wagner (Grundlegung, vol. i, p. 335).
[834] Schmoller especially insists on this point.
[835] Knies, op. cit., p. 23.
[836] A. Wagner, Grundlegung, § 67.