-----Original Message-----
From: ROSEN Forum [mailto:***On Behalf Of Roberto Poli
Sent: Saturday, June 14, 2003 8:57 AM
To: ***
Subject: Re: Sci-Am: Ladders of Effective Theories
Tim,the idea of resorting to self-referential structures goes obviously against the infinite regress advocated by the sci-am article. This doesn't exclude the possibility of a number (I am not saying series) of self-referential structures, variously interconnected one another. Consider "social phenomena": politics, language, art, law, etc etc. Each of them constitute a self-referential system, which at the same time is partially independent and partially dependent from other systems. Biology shares the same picture. I have analyzed a number of the connected issues in a paper of mine published a couple of years ago: “The Basic Problem of the Theory of Levels of Reality”, Axiomathes, 2001, 12, 3-4, pp. 261-283. Please note that at that time I did'nt know Rosen's work. You may retrieve the paper from http://www.kluweronline.com/issn/1122-1151. If not, let me know and I will mail it to you.rRoberto,The formalism and math part is definitely an area where I am weak in understanding. :) I think I did adopt the set-theoretic view only because I am used to seeing it from Rosen.Yes, I think that a self-referential structure would be a possible solution. But would that satisfy the view presented in the sci-am article, of some deepest theory with no inputs? I am not sure, myself, but it seems that self-reference is a different way of avoiding the infinite regress than what the author proposes in the article, since each theory still receives inputs in the self-referential case. Perhaps this is what you meant, I am not sure.Wouldn't the self-referential structure make the sequence of (mathematical) theories essentially noncomputable, since - as a dynamic system - they must all be solved simultaneously?Regards,Tim