Lambert and Kant on truth

© Cambridge University Press 2018. Philosophy without history of philosophy, if not empty or blind, is at least dumb. (Wilfrid Sellars, Science and Metaphysics, p. 1) Different reasons motivate us to study Kant's forerunners or contemporaries. First, looking at these thinkers can help us to understand obscure Kantian notions. Second, they were often involved in debates that Kant also reacted to. Studying their works can enable us to judge whether or not he was up to the state of the art of his time, and whether he responded reasonably to it. Third, by contextualizing Kant's reasoning, we may avoid anachronistic interpretations that force him to answer all too directly to present debates, ignoring differences between his and our agendas, assumptions and methodologies. All these motives can help to better apply the principle of charity to Kant's works – and to reveal what, if anything, we can learn from him for today. These motives also guide the present comparison between Kant's understanding of the concept of truth and that of one of his most esteemed contemporaries, the philosopher-scientist Johann Heinrich Lambert. What is Kant's account of truth? Building upon interpretations of issues such as his thing-in-itself/appearance distinction, the distinction between primary and secondary qualities, the concept-ladenness of experience, his account of the unity of judgment or his claims about the necessary relation between the conditions of knowledge and the conditions of objects of knowledge, philosophers have ascribed to Kant a breathtaking variety of competing views. They range from epistemic, coherence and soft correspondence accounts of truth to similarities with Tarski's semantic theory and comparisons with pluralism. Such interpretations have also been connected to the comprehensive issue of the meaning and justification of Kant's doctrines of transcendental idealism and empirical realism. His claims concerning the concept of truth can seemingly be made to fit with all of these readings, and no consensus is in sight. Rather than starting from any of the issues just mentioned, I shall lay new ground here by analysing Kant's views against the background of Lambert's. Admittedly, Kant does not explicitly refer to Lambert on the topic of truth. My aim here is not to prove causal influences, though there are various pieces of circumstantial evidence for them. We know that they thought highly of each other.