David William Sullivan

Frege's advances in the development of quantification have rarely been subjected to historical interpretation. While the characterization of existence as a second-order concept awaited the invention of the Begriffsschrift, important philosophical innovations had taken place since Kant's critique of the ontological argument. In particular, Herbart had re-conceptualized the nature of existential judgement and this was recognized and adopted by Brentano. In this light, thepossible influence of Herbart and Brentano (or their schools) upon Frege's work is elaborated and critically considered.

Once upon a time, Frege influenced Husserl. More precisely, Frege's scathing review of Philosophie der Arithmetik induced Husserl to abandon his commitment to logical psychologism. There are many different reasons for dismissing this traditional tale. Yet at least one widely circulated claim cannot be upheld, for it is rooted in the false belief that Frege held logic to be an essentially normative science. Rather, Frege and Husserl are united by their shared conception of logic as the maximally general theoretical science. Further, it is proposed that Frege indeed may have influenced Husserl in the movement from psychologism to phenomenology. This time, however, the novel possibility is entertained that Frege provided Husserl with nothing less than an initial rationale of the very need for a phenomenology: the epistemological clarification of the cognitive sources of "pure logic". Along the way, Frege's peculiar Kantianism is revealed to be of a piece with his philosophical contemporaries, the neo-Kantians, in its dependence upon the central notion of a source of knowledge. As a key component of Frege's theory, it is revealed not as an artefact of the new logic but rather as part of the earliest picture which serves to undergird Frege's views on the nature of epistemological justification

Frege's historical milieu is investigated under the rubric of the "neo-Kantian paradigm." This term is used loosely to describe those philosophers in the fourth generation after Kant who went back to Kant in protest to the vulgar or scientific materialism which had prevailed in the previous decades. This paradigm is characterized in a linguistic or conceptual fashion, after the historical precedent of the so-called "Cambridge school" . ;Frege's relation to the neo-Kantians of his own day, to Lotze, and to Herbart and the Brentano school are examined. Correlations are traced between the motivations and the impetus for the development of the "new logic" in light of the increasing emphasis upon logic and its relation to thought by such figures as Lotze, Cohen, Natorp, and Husserl. Frege's own developments are then outlined by illustrating how the functional innovations of his Begriffsschrift made possible new accounts of negation, numerical and existential quantification, and the notion of the object, but are accomplished nonetheless against the backdrop of the work of such thinkers as Herbart, Lotze, Stumpf, and Marty. Finally, this historical interpretation is brought to bear on a much-debated topic in the recent literature: Frege's two stipulations of the logical form of the statement of number