• David Sullivan  “Frege on the Statement of Number”, in: Philosophy and Phenomenological Research, vol. 50, no. 3, 1990

1〜2ページ目にこうある。

[…] Frege's central doctrine that “the content of a statement of number is an assertion about a concept.” This doctrine provides a key element in Frege's logicist project […] But could this fundamental idea conceivably have appeared before Frege? It did. In one of his major works, the Psychologie als Wissenschaft, the now obscure nineteenth-century philosopher Johann Friedrich Herbart (1776-1841) set forth a theory of number surprisingly similar to Frege's, in direct opposition to the one suggested by Kant. […]

Kantにとって数とは、時間の流れのなかで、同類の単位(homogeneous units)を継続的に加えてまとめ上げた結果みたいである。FregeもHerbartもこの意見には反対のようだ。

  • Jonathan P. Seldin  “Curry's Formalism as Structuralism”, Presented to the Thirty-First Annual Meeting of the Canadian Society for History and Philosophy of Mathematics, Waterloo, Ontario, 4-6 June 2005. Revised version, submitted to Philosophia Mathematica.

Abstract
In 1939, Curry proposed a philosophy of mathematics he called formalism. He made this proposal in two works originally written in 1939. These are the two philosophical works for which Curry is known, and they have left a false impression of his views. In this article, I propose to clarify Curry’s views by referring to some of his later writings on the subject. I claim that Curry’s philosophy was not what is now usually called formalism, but is really a form of structuralism.

CurryのPhilosophy of Mathematicsは、Stewart Shapiroの言う意味でのStructuralismに似ているそうである。