Rescuing Perception: Diagrams in Peirce’s theory of cognitive activity

Introduction Commenting on Pearson’s Grammar of Science, Peirce says: “Professor Pearson ... tells us that each of us is like the operator at a central telephone office, shut out from the external world, of which he is informed only by senseimpressions.” (CP 8.144). Peirce found such a position untenable. However, this was neither because he believed that senses do not have a role to play in cognition, nor because he conceived of concepts as cut off from all empirical content. Like Kant, he endeavoured to elaborate an epistemology that, while running against empiricist and rationalist ones, combines elements of both of them. Thus, in a projected book on which he was working in 1861, but never finished, Peirce noted what he considered to be two of Kant’s basic ideas: first, that all cognitions contain a sensual element, and second, that every cognition rests on inferences. (Peirce in Hoopes, 1999, p. 17). These two Kantian ideas clearly run throughout Peirce’s work, and yet he took a different path from Kant. According to Peirce, Kant “drew too hard a line between the operations of observation and of ratiocination.” (CP 1.35). In an attempt to overcome Kant’s scepticism, he restored to perception the epistemological role that it had lost since Plato. Not only did he theorize the relationship between the sensual and the conceptual differently, but also made perception the central tenet of the theoretical formulation of his three categories of being. Perception also became a central feature of Peirce’s conception of cognitive activity. Indeed, in an important sense, in his account, diagrams appear as the semiotic artefacts of an epistemic subject engaged in the search for the truth that, with Kant, had become beyond human reach. Diagrams are at the heart of Peirce’s remarkable endeavour in the restoration of truth –an endeavour that, nevertheless, remains incessantly haunted by Kant’s ghost. In this paper, I discuss the role of diagrammatic thinking within the larger context of Peirce’s semiotic theory of cognitive activity and its underpinning ontology. More specifically, after a short overview of Kant’s scepticism in its historical context in section 1, I discuss, in section 2, Peirce’s attempt to rescue perception as a way to reconceptualize the Kantian “manifold of senses”. In section 3, I argue that Peirce’s redemption of perception led him to a series of problems that are as fundamental as those that Kant encountered. I contend that the understanding of the difficulties of Peirce’s