Month: March 2007

  • Sequel

    Finite Relativity
    continued

    This afternoon I added a paragraph to The Geometry of Logic that makes it, in a way, a sequel to the webpage Finite Relativity:

    "As noted previously, in Figure 2 viewed as a lattice the 16 digital labels 0000, 0001, etc., may be
    interpreted as naming the 16 subsets of a 4-set; in this case the
    partial ordering in the lattice is the
    structure preserved by the lattice's group of 24 automorphisms-- the same
    automorphism group as that of the 16 Boolean connectives.  If,
    however,
    these 16 digital labels are interpreted as naming the 16 functions from
    a 4-set to a 2-set  (of two truth values, of two colors, of two
    finite-field elements, and so forth), it is not obvious that the notion
    of partial order is relevant.  For such a set of 16 functions, the
    relevant group of automorphisms may be the affine group of A
    mentioned above.  One might argue that each Venn diagram in Fig. 3
    constitutes such a function-- specifically, a mapping of four
    nonoverlapping regions
    within a rectangle to a set of two colors-- and that the diagrams,
    considered simply as a set of two-color mappings, have an automorphism
    group of order larger than 24... in fact, of order 322,560. 
    Whether
    such a group can be regarded as forming part of a 'geometry of
    logic' is open to debate."

    The epigraph to "Finite Relativity" is:

    "This is the relativity problem: to fix objectively a class of
    equivalent coordinatizations and to ascertain the group of transformations S
    mediating between them."

    -- Hermann Weyl, The Classical Groups,
    Princeton University Press, 1946, p. 16

    The added paragraph seems to fit this description.

  • For St. Joseph's Day:

    The Naked Brain

    The cover (pdf) of the Notices of the American Mathematical Society for April 2007 (Mathematics Awareness Month) features a naked disembodied brain (Log24, March 16), courtesy of researchers at the Catholic University of Louvain.

    Related material:

    Log24, Jan. 26

    "... at last she realized
    what the Thing on the dais was.
    IT was a brain.
    A disembodied brain...."
     
    A Wrinkle in Time, by Madeleine L'Engle
    "There could not be an objective test
    that distinguished a clever robot
    from a really conscious person."
     
    -- Daniel Dennett in TIME magazine,
    Daniel Dennett in his office

    Daniel Dennett, Professor of Philosophy
    and Director of the
    Center for Cognitive Studies
    at Tufts University,
    in his office on campus.
    (Boston Globe, Jan. 29, 2006.
    Photo © Rick Friedman.)

    Related recommended
    reading and viewing:

    Tom Wolfe's essay
    "Sorry, But Your Soul Just Died,"
    and a video of an interview
     with Wolfe.

  • The Symmetries of Logic

    Update to
    The Geometry of Logic:

    A detailed description of a group of 16 "logical automorphisms" of the
    16 binary connectives has been given in the paper
    "Simetria y Logica: La notacion de Peirce para los 16 conectivos binarios," by Mireya
    Garcia, Jhon Fredy Gomez, and Arnold Oostra. (Published in the
    Memorias del XII Encuentro de Geometria y sus Aplicaciones,
    Universidad Pedagogica Nacional, Bogota, June 2001; on the Web at

    http://www.unav.es/gep/Articulos/SimetriaYLogica.pdf.)

    The authors do not identify this group as a subgroup of the affine group of A (the finite affine geometry of four dimensions over the two-element field);
    this can serve as an exercise.  Another exercise: determining whether the authors' order-16 group includes all transformations that might reasonably be called "logical automorphisms" of the 16 binary connectives.

  • For St. Patrick:

    The Comparison of the
    Catholic Church and the
    Kingdom of Fairies

    by Thomas Hobbes

    "One of the best examples
    philosophy has to offer of
    so-bad-it's-good.
    Brilliantly funny,
    but Very,
    Very, Wrong."

    -- m14m.net

    See also yesterday's
    Log24 entry on Hobbes.

  • ART WARS continued:

    "Geometry,
     Theology,
     and Politics:

     
    Context and Consequences of 

    the Hobbes-Wallis Dispute"

    (pdf)

    by Douglas M. Jesseph

    Dept. of Philosophy and Religion

    North Carolina State University

    Excerpt:

    "We are left to conclude that there was something significant in
    Hobbes's philosophy that motivated Wallis to engage in the lengthy and
    vitriolic denunciation of all things Hobbesian.

    In point of fact, Wallis made no great secret of his motivations for
    attacking Hobbes's geometry, and the presence of theological and
    political motives is well attested in a 1659 letter to Huygens. He
    wrote:

    But regarding the very harsh diatribe against Hobbes, the
    necessity of the case, and not my manners, led to it. For you see, as I
    believe, from other of my writings how peacefully I can differ with
    others and bear those with whom I differ. But this was provoked by our
    Leviathan (as can be easily gathered fro his other writings,
    principally those in English), when he attacks with all his might and
    destroys our universities (and not only ours, but all, both old and
    new), and especially the clergy and all institutions and all religion.
    As if the Christian world knew nothing sound or nothing that was not
    ridiculous in philosophy or religion; and as if it has not understood
    religion because it does not understand philosophy, nor philosophy
    because it does not understand mathematics. And so it seemed necessary
    that now some mathematician, proceeding in the opposite direction,
    should show how little he understand this mathematics (from which he
    takes his courage). Nor should we be deterred from this by his
    arrogance, which we know will vomit poison and filth against us.
    (Wallis to Huygens, 11 January, 1659; Huygens 1888-1950,* 2: 296-7)

    The threats that Hobbes supposedly posed to the universities, the
    clergy, and all religion are a consequence of his political and
    theological doctrines. Hobbes's political theory requires that the
    power of the civil sovereign be absolute and undivided. As a
    consequence, such institutions as universities and the clergy must
    submit to the dictates of the sovereign in all matters. This extends,
    ironically enough, to geometry, since Hobbes notoriously claimed that
    the sovereign could ban the teaching of the subject and order 'the
    burning of all books of Geometry' if he should judge geometric
    principles 'a thing contrary to [his] right of dominion, or to the
    interest of men that have dominion' (Leviathan (1651) 1.11, 50; English Works**
    3: 91). In the area of church government, Hobbes's doctrines are a
    decisive rejection of the claims of Presbyterianism, which holds that
    questions of theological doctrine is [sic] to be decided by the
    elders of the church-- the presbytery-- without reference to the claims
    of the sovereign. As a Presbyterian minister, a doctor of divinity, and
    professor of geometry at Oxford, Wallis found abundant reason to reject
    this political theory."

    * Huygens, Christiaan. 1888-1950. Les oeuvres complètes de Chrisiaan Huygens. Ed. La Société Hollandaise des Sciences. 22 vols. The Hague: Martinus Nijhoff.

    ** Hobbes, Thomas. [1839-45] 1966. The English Works of Thomas Hobbes of Malmesbury, now First Collected and Edited by Sir William Molesworth. Edited by William Molesworth. 11 vols. Reprint. Aalen, Germany: Scientia Verlag.

    Related material:

    "But what is it?"
    Calvin demanded.
    "We know that it's evil,
    but what is it?"

    "Yyouu hhave ssaidd itt!"
    Mrs. Which's voice rang out.
    "Itt iss Eevill. Itt iss thee
    Ppowers of Ddarrkknesss!"

    -- A Wrinkle in Time

    The image “http://www.log24.com/log/pix07/070316-AMScover.jpg” cannot be displayed, because it contains errors.

    "After A Wrinkle in Time was
    finally published, it was pointed out to me that the villain, a naked
    disembodied brain, was called 'It' because It stands for Intellectual
    truth as opposed to a truth which involves the whole of us, heart as
    well as mind.  That acronym had never occurred to me.  I chose the name
    It intuitively, because an IT does not have a heart or soul.  And I did
    not understand consciously at the time of writing that the intellect,
    when it is not informed by the heart, is evil."

    See also

    "Darkness Visible"

    in ART WARS.

  • Philosophy Wars continued:

    Boink, Boink

    From the April Notices of the
    American Mathematical Society
    :

    Mathematics and Philosophy, AMS Notices, April 2007

    From Log24
    on March 15 last year,
    the annual pie-eating
    contest of the Harvard
    Mathematics Department
    on Pi Day:

    Etiquette at Harvard

    From Log24 yesterday:

    Quotation for Pi Day: Boink, Boink

    Click on the above sections
    for further details.

  • For Pi Day:

    "'It is a very difficult philosophical question, the question of
    what "random" is,' he said. He plucked the rubber band with his
    thumb, boink, boink."

    -- Herbert Robbins in Richard Preston's "The Mountains of Pi" (The New Yorker, March 2, 1992)

  • ART WARS continued

    The Logic of Dreams

    From A Beautiful Mind--

    "How
    could you," began Mackey, "how could you, a mathematician, a man
    devoted to reason and logical proof...how could you believe that
    extraterrestrials are sending you messages? How could you believe that
    you are being recruited by aliens from outer space to save the world?
    How could you...?"

    Nash looked up at last and fixed Mackey with
    an unblinking stare as cool and dispassionate as that of any bird or
    snake. "Because," Nash said slowly in his soft, reasonable southern
    drawl, as if talking to himself, "the ideas I had about supernatural
    beings came to me the same way that my mathematical ideas did. So I
    took them seriously."

    Ideas:

    The image “http://www.log24.com/log/pix07/070309-NYlottery.jpg” cannot be displayed, because it contains errors.

    The image “http://www.log24.com/log/pix07/070309-PAlottery.jpg” cannot be displayed, because it contains errors.

    These
    numbers may, in the mad way so well portrayed by Sylvia Nasar in the
    above book, be regarded as telling a story... a story that should, of
    course, not be taken too seriously.

    Friday's New York numbers (midday 214, evening 711) suggest the dates 2/14 and 7/11
    Clicking on these dates will lead the reader to Log24 entries
    featuring, among others, T. S. Eliot and Stephen King-- two authors not
    unacquainted with the bizarre logic of dreams.

    A link in the 7/11 entry leads to a remark of Noel Gray on Plato's Meno and "graphic
    austerity as the tool to bring to the surface, literally and
    figuratively, the inherent presence of geometry in the mind of the
    slave."

    Also Friday: an example of graphic austerity-- indeed, Gray graphic austerity-- in Log24:

    Chessboard (Detail)

    This
    illustration refers to chess rather than to geometry, and to the mind
    of an addict rather than to that of a slave, but chess and
    geometry, like addiction and slavery, are not unrelated.


    Friday's
    Pennsylvania numbers, midday 429 and evening 038, suggest that the
    story includes, appropriately enough in view of the above Beautiful Mind excerpt, Mackey himself.  The midday number suggests the date 4/29, which at Log24 leads to an entry in memory of Mackey.

    (Related material: the Harvard Gazette of April 6, 2006, "Mathematician George W. Mackey, 90: Obituary"--  "A memorial service will be held at Harvard's Memorial Church on April 29 at 2 p.m.")

    Friday's Pennsylvania evening number 038 tells two other parts of the story involving Mackey...

    As Mackey himself might hope, the number may be regarded as a reference to the 38 impressive pages of Varadarajan's "Mackey Memorial Lecture" (pdf).

    More
    in the spirit of Nash, 38 may also be taken as a reference to
    Harvard's old postal address, Cambridge 38, and to the year, 1938, that
    Mackey entered graduate study at Harvard, having completed his
    undergraduate studies at what is now Rice University.

    Returning
    to the concept of graphic austerity, we may further simplify the
    already abstract chessboard figure above to obtain an illustration that
    has been called both "the field of reason" and "the Garden of Apollo"
    by an architect, John Outram, discussing his work at Mackey's undergraduate alma mater:

    The image “http://www.log24.com/theory/images/grid3x3.gif” cannot be displayed, because it contains errors.

    Let us hope that Mackey,
    a devotee of reason,
    is now enjoying the company
    of Apollo rather than that of
    Tom O'Bedlam:

    The image “http://www.log24.com/log/pix05A/050613-Crowe.jpg” cannot be displayed, because it contains errors.

    For John Nash on his birthday:

    I know more than Apollo,
    For oft when he lies sleeping
    I see the stars at mortal wars
    In the wounded welkin weeping.

    -- Tom O'Bedlam's Song

  • A philosopher's geometry:

    Tesseract

    A new page at finitegeometry.org,
    The Geometry of Logic,
    includes the following figure:

    The 16 binary connectives arranged in a tesseract

    "There is such a thing
    as a tesseract.
    "

    -- Madeleine L'Engle
     

  • Chess novel:

    Queen's Gambit

    Chessboard (Detail)

    That the topless towers be burnt

    And men recall that face,

    Move most gently if move you must

    In this lonely place.

    She thinks, part woman, three parts a child,

    That nobody looks; her feet

    Practise a tinker shuffle

    Picked up on a street.
    Like a long-legged fly upon the stream

    Her mind moves upon silence.

    -- W. B. Yeats, "Long-Legged Fly"

    This is the epigraph to
    the Walter Tevis novel
    The Queen's Gambit.