General abstract: The main topic of the panel is to discuss how epistemology and ontology articulate in Peirce's philosophy, from a naturalistic account of the genesis of knowledge. The first presentation will discuss Peirce's theory of abduction and critical common-sensism; the second will discuss Peirce's thesis on the co-naturality between mind and reality in the light of his phenomenological categories; the third one will discuss Peirce's concept of absolute chance as real possibility; and the fourth will discuss the importance of Peirce's semiotic of symbols for his conception of God as cognizable. 

Peirce always defended a metaphysical realism opposed to nominalist tendencies in philosophy. Defending the idea that only the real can fix our beliefs, for its irreducible character of being alter for human consciousness, Peirce came to the hypothesis of the co-naturality between mind and reality as the ground for the idea that whatever is possible to exist is cognizable in semiotic terms, that is, can be translated into signs. The co-naturality between mind and matter is at the core of Peirce's defence of chance as real, as an indeterminate pure potentiality that reacts as an existing phenomenon in nature.

Now, Peirce explains this co-naturality in evolutionary terms: human mind is like an instinct we evolutionarily developed through ages, as if we were “building a cantilever bridge” of inferences, as he says in the essay about the neglected argument for the reality of God, that we continuously test in experience, aiming to reach a clearer comprehension of reality and of ourselves. From the most basic and empirical to the most abstract and metaphysical – up to the point of devising a symbolic conception of God – retroduction is a form of reasoning we developed – it is just the same a result from the evolution of the species as any other (as the muscles that move our hands and thumbs, for instance). All human knowledge, therefore, comes from, expands from and enhances with a basis upon natural instincts. This idea is very important for Peirce's theory of abduction, or retroduction, as he sometimes says. According to him, retroduction is the only form of reasoning furnishing an explanatory hypothesis for surprising experiential facts, similar in form to a fallacy of affirming the consequent. This means that from observed (unpredicted) facts, we retroduce in search for an explanatory hypothesis of what might have caused those facts. This form of reasoning, of course, has no safety at all, it is highly fallible, but is the only one that can give us an explanation of why what happens, happens the way it does. As he himself says, it's the only way to find an explanation, for deduction and induction, by their very logical natures, only establish the necessary consequences of an already known setup and search for confirmatory facts, respectively. No amplification of the realm of knowledge is obtained by them.

The relevance of this panel for Conference is in the emphasis it poses on the naturalistic and metaphysical aspects of Peirce's philosophy without separating them, trying to avoid reductionist “analytical” readings of Peirce, stressing both his theory of knowledge and scientific method and his most abstract and difficult ideas with equal weight.