14.0638 black-box vs glass-box methods?

From: by way of Willard McCarty (willard@lists.village.Virginia.EDU)
Date: Sat Feb 03 2001 - 05:41:09 EST

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                   Humanist Discussion Group, Vol. 14, No. 638.
           Centre for Computing in the Humanities, King's College London

             Date: Sat, 03 Feb 2001 10:33:06 +0000
             From: Willard McCarty <willard.mccarty@kcl.ac.uk>
             Subject: black box vs. glass box

    This is a question about how we as computing humanists deal with complex

    In physics, as I recall, the term "black box" refers to a device or process
    whose internals cannot be known directly. You can measure the inputs and
    outputs but cannot see what is inside. As a student of 2nd-year physics at
    Berkeley, I was given a metal box with input and output terminals, and with
    the aid of a signal generator, voltage meter and oscilloscope was supposed
    to discover what was inside. (I don't remember whether I completed the
    assignment successfully, but I was certainly intrigued.)

    Nowadays programmers checking code have the choice between a black-box and
    a glass-box approach. In the former what you do is, as in the example from
    physics, use various inputs to generate outputs and by the latter tell
    whether the code is correct or not. In the glass-box approach the
    programmer checks the code itself, step by step. The latter becomes harder
    and harder to do as the code becomes more complex; under certain conditions
    it is simply impossible.

    Less prejudicially, perhaps, but more analytically the black-box approach
    may be defined as
    >A strategy for investigating a complex object without knowledge or
    >assumptions about its internal make-up, structure or parts. The method
    >aims at either a formal description of the transformation rules linking
    >inputs and outputs or the construction of a model exhibiting a behavior
    >that approximates what is observable from the outside of the "black box".

    Now for my point, which is to say, question. Consider the following two
    fictitious scenarios:

    (1) In the investigation of a complex matter in a large text, a researcher
    applies various sophisticated statistical methods to the text. Let us say
    that these methods yield very interesting, highly significant results in
    the light of what scholars know about the text and from their experience of
    it. Nevertheless, the researcher in question does not understand how these
    methods work in any detail nor can he or she justify the use of the
    particular methods used, rather than others available for the task. All
    that he or she knows is that they work, i.e. yield interesting results.

    (2) Another researcher, investigating a piece of music, uses various
    complex transformation routines to alter the sequence and/or timing of the
    notes. Let us say that one of the transformations reveals something highly
    significant about the music that no one has ever noticed before. But this
    researcher also does not understand the transformation and cannot justify
    its use rather than another.

    In both cases, how should we regard the researchers' use of these black-box
    methods? Are they by principles of good scholarship obliged to determine
    how their black boxes work? Could we say that in our domain use of the
    black box is fine as a way of getting inspired but that we shouldn't call
    the practice humanities computing unless the research goes on to pry into
    the box? If we are obliged to understand, then at what level? As in the
    definition of primitives, can we say that past a certain point we do not
    have to know, but before it we do? Thus, I might argue, since sorting a
    list of words is a primitive, I don't need to be able to follow the code
    that does the sort. I can, however, imagine someone saying that I should be
    able to understand the logic of the process.

    Comments? Better questions?


    Dr Willard McCarty / Senior Lecturer /
    Centre for Computing in the Humanities / King's College London /
    Strand / London WC2R 2LS / U.K. /
    +44 (0)20 7848-2784 / ilex.cc.kcl.ac.uk/wlm/

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