[peirce-l] Re: Sinsign, Legisign, Qualisign - help!

[Jerry LR Chandler]

Dear Jim, Rob and List: Before turning to Jim's post, a couple of comments about the Salzburg conferences. The Whitehead conference attracted about three hundred (300!!) participants.  The Chinese are keenly interested in Whitehead.  It was rumored that they intend to establish 25 research institutes to explore philosophical and political relations.  The sessions on mathematics, physics, chemistry and biology attracted about 25 participants to each!  very impressive relative to other philosophical conferences. Peirce was frequently mentioned in sessions.  A special session included discussions about the Whitehead - deChardin linkages.  Roland Faber's paper suggested to me an orthogonality between these two views of philosophy.  By orthogonality in this context I mean the approach to extensions. The abstracts are on the web and papers will also be posted on the website for the conference. The Biosemiotics gathering was attended by about 50 participants from perhaps a dozen different countries.  Peirce played a role in many many papers.  The abstracts are on the web and the papers will be posted.  Lots of discussions of coding and bio-logic. Is it not absolutely wonderful that we can access current research reports from our desktops in a timely and efficient manner?   Now,  on to the issue of Peirce and chemical isomers that are distinguished by a specific property of rotating light that has passed through a crystal, generating what is called "polarized light."   Jim wrote: From: "Jim Piat" <[EMAIL PROTECTED]> Date: Mon, 3 Jul 2006 18:17:21 -0400 X-Message-Number: 7 Jerry Chandler wrote: "But, my point is that if four different groups are necessary to = construct an optical isomer of carbon such that it distinguishes between = the logic of polarized light, then it is mathematically impossible to = achieve this logical distinction with any notion of 'threeness".  = Optical isomers are not a question of trichotomies and triadicies.  They = are questions of tetrachotomies and tetraadicies.  I would welcome = arguments to the otherwise". Dear Jerry, =20 Actually, handedness and materials that polarize light are among the = very examples Peirce gives of his notion of Thirdness.   Do you have a direct source of this passage?   The notions of = left verses right (which distinguished between mirror image optical = stereo-isomers) Peirce pointa out require the consideration of the = triadic relation of three directions (up-down,  front back, left right). = It may well be that different carbon groups are involved naturally = occuring steroisomers but in fact only three conjoined points are = required to achieved the distniction beween left and right. This is an interesting point.   Of course, it refers to the cartesian plane, not space itself. In general, chemistry operates in space and optical isomers rotate light is space. Triadic  examples of handedness Left                       Right A-------B                 B------A           l                   l           l                   l          C                  C Verses "redundant" tetradic examples of handedness Left                                        Right A------B------D                 D--------B---------A          l                                     l          I                                     I          C                                   C I don't mean to be present the above as authoritative  -- this is merely = my understanding of the issue.=20 Modern theory (simplified) considers light rotation to be a spatial operation emerging from the difference between four DIFFERENT material attachments to a central carbon atom. In order to deduce the relation with "left" or "right", one starts with the concept of a tetrahedron. Hold the tetrahedron in space and imagine looking down one of the apexes through the middle point (the central carbon atom) and out the plane opposite the apex and middle point. The "back plane" will contain the other three points of the tetrahedron.   These three points can be in two possible orders:    A - B  - C  or A - C - B. Pastuer noticed that two crystal forms of tartaric acid existed and was able to separate them "by eye". One rotated light left, the other right.  Many years later it was found that two crystalline forms of tartaric acid with identical molecular formula and structure, represented the order A_B_C or the order A_C_B, differed by the organization in space.   This is a slightly simplified version of the narrative but captures the essential features. From a philosophy of science perspective, the existence of optical isomers clears shows the irreducibility of chemistry knowledge to independent physical concepts.  As nearly all biochemical molecules are optical isomers, often having hundreds or thousands of optical centers, it is widely believed that a theory of biology depends on explaining the origins of optical isomerism in living systems. I certainly would appreciate any insights individuals may have on how this related to Thirdness, given the starting point of valence and the 1868 paper on extension of paths as either linear or branching. Best wishes and good luck witht he conference, Jim Piat Thanks for the response. Cheers Jerry --- Message from peirce-l forum to subscriber archive@mail-archive.com