On 12/31/2017 7:14 AM, Auke van Breemen wrote:
I am unsure about the place of modality, but maybe it just boils down to a firstness and secondness view on the issue.
Historical note: Aristotle claimed that necessity and possibility are determined by the laws of nature. Leibniz introduced possible worlds with necessity as truth in all possible worlds, and possibility as truth in at least one. Carnap was a strict nominalist who followed Mach in claiming that the laws of science are *nothing but* summaries of observable data. He even considered *truth* to be outside the realm of "scientific" method. But Tarski's model theory convinced him that truth could be defined in observable terms. Carnap later (1947) combined Leibniz and Tarski. Hintikka introduced "model sets", which consisted of sets of propositions that are true of the possible worlds. He also introduced an alternativity relation among model sets. Kripke went back to sets of worlds and related the accessibility relation (identical to Hintikka's alternativity) to the axioms for modality that C. I. Lewis had introduced. Nominalists preferred sets of worlds to sets of sets of propositions. But Quine would not accept modality with either version. But in 1973, Michael Dunn introduced a beautiful solution that Peirce would love, but the nominalists would hate: treat each possible world as a pair (facts, laws). For a six-page review of these issues with references, see http://jfsowa.com/pubs/5qelogic.pdf . For more detail (26 pages), see http://jfsowa.com/pubs/worlds.pdf . John
----------------------------- PEIRCE-L subscribers: Click on "Reply List" or "Reply All" to REPLY ON PEIRCE-L to this message. PEIRCE-L posts should go to peirce-L@list.iupui.edu . To UNSUBSCRIBE, send a message not to PEIRCE-L but to l...@list.iupui.edu with the line "UNSubscribe PEIRCE-L" in the BODY of the message. More at http://www.cspeirce.com/peirce-l/peirce-l.htm .
