[lit-ideas] amT

  • From: "palma@xxxxxxxxxx" <palmaadriano@xxxxxxxxx>
  • To: lit-ideas@xxxxxxxxxxxxx
  • Date: Sat, 14 Jan 2012 15:44:11 +0200

* The Argument from Consciousness*

This argument is very, well expressed in Professor Jefferson's Lister
Oration for 1949, from which I quote. "Not until a machine can write a
sonnet or compose a concerto because of thoughts and emotions felt, and not
by the chance fall of symbols, could we agree that machine equals
brain-that is, not only write it but know that it had written it. No
mechanism could feel (and not merely artificially signal, an easy
contrivance) pleasure at its successes, grief when its valves fuse, be
warmed by flattery, be made miserable by its mistakes, be charmed by sex,
be angry or depressed when it cannot get what it wants."

This argument appears to be a denial of the validity of our test. According
to the most extreme form of this view the only way by which one could be
sure that machine thinks is to be the machine and to feel oneself thinking.
One could then describe these feelings to the world, but of course no one
would be justified in taking any notice. Likewise according to this view
the only way to know that a man thinks is to be that particular man. It is
in fact the solipsist point of view. It may be the most logical view to
hold but it makes communication of ideas difficult. A is liable to believe
"A thinks but B does not" whilst B believes "B thinks but A does not."
instead of arguing continually over this point it is usual to have the
polite convention that everyone thinks.

I am sure that Professor Jefferson does not wish to adopt the extreme and
solipsist point of view. Probably he would be quite willing to accept the
imitation game as a test. The game (with the player B omitted) is
frequently used in practice under the name of viva voce to discover whether
some one really understands something or has "learnt it parrot fashion."
Let us listen in to a part of such a *viva voce*:

Interrogator: In the first line of your sonnet which reads "Shall I compare
thee to a summer's day," would not "a spring day" do as well or better?

Witness: It wouldn't scan.

Interrogator: How about "a winter's day," That would scan all right.

Witness: Yes, but nobody wants to be compared to a winter's day.

Interrogator: Would you say Mr. Pickwick reminded you of Christmas?

Witness: In a way.

Interrogator: Yet Christmas is a winter's day, and I do not think Mr.
Pickwick would mind the comparison.

Witness: I don't think you're serious. By a winter's day one means a
typical winter's day, rather than a special one like Christmas.

And so on, What would Professor Jefferson say if the sonnet-writing machine
was able to answer like this in the *viva voce*? I do not know whether he
would regard the machine as "merely artificially signalling" these answers,
but if the answers were as satisfactory and sustained as in the above
passage I do not think he would describe it as "an easy contrivance." This
phrase is, I think, intended to cover such devices as the inclusion in the
machine of a record of someone reading a sonnet, with appropriate switching
to turn it on from time to time.

In short then, I think that most of those who support the argument from
consciousness could be persuaded to abandon it rather than be forced into
the solipsist position. They will then probably be willing to accept our
test.

I do not wish to give the impression that I think there is no mystery about
consciousness. There is, for instance, something of a paradox connected
with any attempt to localise it. But I do not think these mysteries
necessarily need to be solved before we can answer the question with which
we are concerned in this paper.

*(5) Arguments from Various Disabilities*

These arguments take the form, "I grant you that you can make machines do
all the things you have mentioned but you will never be able to make one to
do X." Numerous features X are suggested in this connexion I offer a
selection:

Be kind, resourceful, beautiful, friendly, have initiative, have a sense of
humour, tell right from wrong, make mistakes, fall in love, enjoy
strawberries and cream, make some one fall in love with it, learn from
experience, use words properly, be the subject of its own thought, have as
much diversity of behaviour as a man, do something really new.

No support is usually offered for these statements. I believe they are
mostly founded on the principle of scientific induction. A man has seen
thousands of machines in his lifetime. From what he sees of them he draws a
number of general conclusions. They are ugly, each is designed for a very
limited purpose, when required for a minutely different purpose they are
useless, the variety of behaviour of any one of them is very small, etc.,
etc. Naturally he concludes that these are necessary properties of machines
in general. Many of these limitations are associated with the very small
storage capacity of most machines. (I am assuming that the idea of storage
capacity is extended in some way to cover machines other than
discrete-state machines. The exact definition does not matter as no
mathematical accuracy is claimed in the present discussion,) A few years
ago, when very little had been heard of digital computers, it was possible
to elicit much incredulity concerning them, if one mentioned their
properties without describing their construction. That was presumably due
to a similar application of the principle of scientific induction. These
applications of the principle are of course largely unconscious. When a
burnt child fears the fire and shows that he fears it by avoiding it, f
should say that he was applying scientific induction. (I could of course
also describe his behaviour in many other ways.) The works and customs of
mankind do not seem to be very suitable material to which to apply
scientific induction. A very large part of space-time must be investigated,
if reliable results are to be obtained. Otherwise we may (as most English
'Children do) decide that everybody speaks English, and that it is silly to
learn French.

There are, however, special remarks to be made about many of the
disabilities that have been mentioned. The inability to enjoy strawberries
and cream may have struck the reader as frivolous. Possibly a machine might
be made to enjoy this delicious dish, but any attempt to make one do so
would be idiotic. What is important about this disability is that it
contributes to some of the other disabilities, e.g., to the difficulty of
the same kind of friendliness occurring between man and machine as between
white man and white man, or between black man and black man.

The claim that "machines cannot make mistakes" seems a curious one. One is
tempted to retort, "Are they any the worse for that?" But let us adopt a
more sympathetic attitude, and try to see what is really meant. I think
this criticism can be explained in terms of the imitation game. It is
claimed that the interrogator could distinguish the machine from the man
simply by setting them a number of problems in arithmetic. The machine
would be unmasked because of its deadly accuracy. The reply to this is
simple. The machine (programmed for playing the game) would not attempt to
give the right answers to the arithmetic problems. It would deliberately
introduce mistakes in a manner calculated to confuse the interrogator. A
mechanical fault would probably show itself through an unsuitable decision
as to what sort of a mistake to make in the arithmetic. Even this
interpretation of the criticism is not sufficiently sympathetic. But we
cannot afford the space to go into it much further. It seems to me that
this criticism depends on a confusion between two kinds of mistake, We may
call them "errors of functioning" and "errors of conclusion." Errors of
functioning are due to some mechanical or electrical fault which causes the
machine to behave otherwise than it was designed to do. In philosophical
discussions one likes to ignore the possibility of such errors; one is
therefore discussing "abstract machines." These abstract machines are
mathematical fictions rather than physical objects. By definition they are
incapable of errors of functioning. In this sense we can truly say that
"machines can never make mistakes." Errors of conclusion can only arise
when some meaning is attached to the output signals from the machine. The
machine might, for instance, type out mathematical equations, or sentences
in English. When a false proposition is typed we say that the machine has
committed an error of conclusion. There is clearly no reason at all for
saying that a machine cannot make this kind of mistake. It might do nothing
but type out repeatedly "O = I." To take a less perverse example, it might
have some method for drawing conclusions by scientific induction. We must
expect such a method to lead occasionally to erroneous results.

The claim that a machine cannot be the subject of its own thought can of
course only be answered if it can be shown that the machine has some
thought with some subject matter. Nevertheless, "the subject matter of a
machine's operations" does seem to mean something, at least to the people
who deal with it. If, for instance, the machine was trying to find a
solution of the equation x2 - 40x - 11 = 0 one would be tempted to describe
this equation as part of the machine's subject matter at that moment. In
this sort of sense a machine undoubtedly can be its own subject matter. It
may be used to help in making up its own programmes, or to predict the
effect of alterations in its own structure. By observing the results of its
own behaviour it can modify its own programmes so as to achieve some
purpose more effectively. These are possibilities of the near future,
rather than Utopian dreams.

The criticism that a machine cannot have much diversity of behaviour is
just a way of saying that it cannot have much storage capacity. Until
fairly recently a storage capacity of even a thousand digits was very rare.

The criticisms that we are considering here are often disguised forms of
the argument from consciousness, Usually if one maintains that a machine
can do one of these things, and describes the kind of method that the
machine could use, one will not make much of an impression. It is thought
that tile method (whatever it may be, for it must be mechanical) is really
rather base. Compare the parentheses in Jefferson's statement quoted on
page 22.

*(6) Lady Lovelace's Objection*

Our most detailed information of Babbage's Analytical Engine comes from a
memoir by Lady Lovelace ( 1842). In it she states, "The Analytical Engine
has no pretensions to*originate* anything. It can do *whatever we know how
to order it* to perform" (her italics). This statement is quoted by Hartree
( 1949) who adds: "This does not imply that it may not be possible to
construct electronic equipment which will 'think for itself,' or in which,
in biological terms, one could set up a conditioned reflex, which would
serve as a basis for 'learning.' Whether this is possible in principle or
not is a stimulating and exciting question, suggested by some of these
recent developments But it did not seem that the machines constructed or
projected at the time had this property."

I am in thorough agreement with Hartree over this. It will be noticed that
he does not assert that the machines in question had not got the property,
but rather that the evidence available to Lady Lovelace did not encourage
her to believe that they had it. It is quite possible that the machines in
question had in a sense got this property. For suppose that some
discrete-state machine has the property. The Analytical Engine was a
universal digital computer, so that, if its storage capacity and speed were
adequate, it could by suitable programming be made to mimic the machine in
question. Probably this argument did not occur to the Countess or to
Babbage. In any case there was no obligation on them to claim all that
could be claimed.

This whole question will be considered again under the heading of learning
machines.

A variant of Lady Lovelace's objection states that a machine can "never do
anything really new." This may be parried for a moment with the saw, "There
is nothing new under the sun." Who can be certain that "original work" that
he has done was not simply the growth of the seed planted in him by
teaching, or the effect of following well-known general principles. A
better variant of the objection says that a machine can never "take us by
surprise." This statement is a more direct challenge and can be met
directly. Machines take me by surprise with great frequency. This is
largely because I do not do sufficient calculation to decide what to expect
them to do, or rather because, although I do a calculation, I do it in a
hurried, slipshod fashion, taking risks. Perhaps I say to myself, "I
suppose the Voltage here ought to he the same as there: anyway let's assume
it is." Naturally I am often wrong, and the result is a surprise for me for
by the time the experiment is done these assumptions have been forgotten.
These admissions lay me open to lectures on the subject of my vicious ways,
but do not throw any doubt on my credibility when I testify to the
surprises I experience.

I do not expect this reply to silence my critic. He will probably say that
h surprises are due to some creative mental act on my part, and reflect no
credit on the machine. This leads us back to the argument from
consciousness, and far from the idea of surprise. It is a line of argument
we must consider closed, but it is perhaps worth remarking that the
appreciation of something as surprising requires as much of a "creative
mental act" whether the surprising event originates from a man, a book, a
machine or anything else.

The view that machines cannot give rise to surprises is due, I believe, to
a fallacy to which philosophers and mathematicians are particularly
subject. This is the assumption that as soon as a fact is presented to a
mind all consequences of that fact spring into the mind simultaneously with
it. It is a very useful assumption under many circumstances, but one too
easily forgets that it is false. A natural consequence of doing so is that
one then assumes that there is no virtue in the mere working out of
consequences from data and general principles.

-- 
palma, KZN

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