From: Yusuf Larry (kly198@ecs.soton.ac.uk)
Date: Thu Mar 01 2001 - 15:26:41 GMT
http://cogprints.soton.ac.uk/documents/disk0/00/00/04/99/index.html
> TURING:
> I propose to consider the question, "Can machines think?" This should begin with
> definitions of the meaning of the terms "machine" and "think."
Yusuf L:
Defining what a machine is and what thinking means takes us closer to
understanding the question, however the scope of the question has to been
set. The word "can" also needs to be analyzed. Does this mean that machines
now can think or that someday, machines will be able to think? What if in
principle it is possible for a machine to think, will this be acceptable or
does an actual built working machine have to be used? There is the
possibility that a system that can truly think, would have to be as complex
as thinking systems today i.e. humans. In time we could simulate this
process but simulation is not the real thing.
> TURING:
> Now suppose X is actually A, then A must answer. It is A's object in the game to try and
> cause C to make the wrong identification.
Yusuf L:
This statement suggests that the Imitation game is based on deception. If we
then extend the game to involve a machine, this would imply that if the
machine were, irrespective of the means able to fool C, then it can think or
to be more precise could be a man and is indistinguishable from a human.
The analysis of the question: "can machines think?" using a "game"
introduces the concept of winning and loosing, of right and wrong, which
distracts us from the matter in hand. Hard coding a machine for example,
that could fool C, would not imply that this machine can think but just that
C was not able to identify it as a machine.
> TURING:
> We now ask the question, "What will happen when a machine takes the part of A in this
> game?" Will the interrogator decide wrongly as often when the game is played like this as
> he does when the game is played between a man and a woman? These questions replace
> our original, "Can machines think?"
Yusuf L:
This seems to reinforce the suggestion that if C decides wrongly, then
machines can think. It is little wonder the Loebner prize has such a large
following.
> TURING:
> The form in which we have set the problem reflects this fact in the condition which
> prevents the interrogator from seeing or touching the other competitors, or hearing -their
> voices. ... We do not wish to penalize the machine for its inability to shine
> in beauty competitions, nor to penalize a man for losing in a race against an aeroplane.
> The conditions of our game make these disabilities irrelevant.
Yusuf L:
Here we are encouraged to judge the machine and the human by performance
capacity and not by aesthetics. Hence, a machine that can think is one that
can do what we do, indistinguishably from the way we do it. This has nothing
to do with the look and feel of the system.
> TURING:
> It might be urged that when playing the "imitation game" the best strategy for the
> machine may possibly be something other than imitation of the behaviour of a man. This
> may be, but I think it is unlikely that there is any great effect of this kind.
Yusuf L:
This is a statement to be considered by those who subscribe to developing
systems that can imitate certain actions, or reply the way we would. Maybe
the emphasis needs to be more on developing true systems, i.e. ones that can
truly analyze a question or situation and reply based on an understanding of
this question, rather than on a set of inputs and outputs.
> TURING:
> It is natural that we should wish to permit every kind of engineering technique to be used in
> our machines. We also wish to allow the possibility than an engineer or team of engineers
> may construct a machine which works, but whose manner of operation cannot be
> satisfactorily described by its constructors because they have applied a method, which is
> largely experimental.
Yusuf L:
In building the thinking machine, we should not restrict ourselves to
particular techniques but rather explore every possible form of engineering.
And just like humans can not explicitly describe how it is we think, or how
another person thinks, does something intelligent or in fact if they think
or are intelligent, we may not be able to do the same with the machine or
indeed need to, in order to justify the machine as a thinking system.
> TURING:
> Finally, we wish to exclude from the machines men born in the usual manner. ... for it is
> probably possible to rear a complete individual from a single cell of the skin (say) of a man.
> To do so would be a feat of biological technique deserving of the very highest praise, but we
> would not be inclined to regard it as a case of "constructing a thinking machine."
Yusuf L:
Genetically engineering a person is more reproduction than the construction
of a thinking machine. Even though I agree that humans like machines are
causal systems thus in some sense making them machines, we would not be able
to understand or describe how a genetically engineered person works anymore
than we can describe ourselves. A genetically engineered person will not or
should not be distinguishable from a person because it is a person. It will
not be imitating a person, as it is impossible to imitate ones innate
characteristics. One cannot be more or like oneself and hence has no need
for the imitation game.
> TURING:
> We are the more ready to do so in view of the fact that the present interest in "thinking
> machines" has been aroused by a particular kind of machine, usually called an "electronic
> computer" or "digital computer." Following this suggestion we only permit digital computers
> to take part in our game.
Yusuf L:
Does this restrict our search for our answer to the question, “can
machines think”? For instance, what if a digital computer is incapable of
thinking because our ability to think, be intelligent etc is dependent on
our physiology? John Searle [Searle 1980, Searle 1992], believes that what
we are made of is fundamental to our intelligence. Perhaps the machine that
would be able to think and be intelligent would have to process information
in parallel like the brain and would be able to use true fuzzy logic rather
than an adaptation of binary logic. Such a machine does not fall under the
description of the word digital computer.
> TURING:
> The short answer is that we are not asking whether all digital computers would do well in the
> game nor whether the computers at present available would do well, but whether there are
> imaginable computers, which would do well?
Yusuf L:
Does this mean that when Turing asked the question: “Can machines think”
and started his investigation into computing machinery and intelligence, he
was more concerned with the possibility of a thinking machine rather than a
live demonstration of a thinking machine? Does can really mean, in principle
is it possible for a machine to think?
> TURING:
> A digital computer can usually be regarded as consisting of three parts:
> (i) Store, (ii) Executive unit, (iii) Control.
Yusuf L:
Turing describes the components of a digital computer, which modern day
architectures are still based on. The store is where data and information is
stored during and after processing. The Executive Unit performs the
individual operations involved in performing a task, e.g. a calculation. The
Control performs the instructions specified in the “table of
instructions” at specified times to enable the smooth working of the
system. He the gives a simple example of the instructions the digital
computer would be able to take.
> TURING:
> The reader must accept it as a fact that digital computers can be constructed, and indeed
> have been constructed, according to the principles we have described, and that they can in
> fact mimic the actions of a human computer very closely.
Yusuf L:
Prior to this statement, Turing had described digital computers as machines
capable of performing computation; where computation is
implementation-independent, semantically interpretable, syntactic rule
based, symbol manipulation. Following Turing’s argument of
indistinguishable entities, if this digital computer can mimic the human
computer indistinguishably then it could be the human computer. This implies
that the human computer is simply a machine that performs computation. I
disagree. However, it is possible that a computational system might be able to mimic
some to many of the human computer functions (hence the very closely), in
which case, this is possible but mimicking is as different from being as
simulation is as different from real life.
> TURING:
> An interesting variant on the idea of a digital computer is a "digital computer
> with a random element." …Sometimes such a machine is described as having
> free will (though I would not use this phrase myself).
Yusuf L:
A digital computer is a discrete state machine and so cannot truly be a
random machine. Randomness can be programmed by the aid of algorithms but
the best that can be gotten from this technique based on numbers and
calculation is pseudo-randomness.
> TURING:
> The fact that Babbage's Analytical Engine was to be entirely mechanical will
> help us to rid ourselves of a superstition. Importance is often attached to the
> fact that modern digital computers are electrical, and that the nervous
> system also is electrical. Since Babbage's machine was not electrical, and
> since all digital computers are in a sense equivalent, we see that this use of
> electricity cannot be of theoretical importance.
Yusuf L:
Even if electricity usually comes in where fast signalling is concerned, it
is an implementation specific feature of a digital computer but is not the
sole reason for the machine being a digital computer. We know that in the
nervous system chemical phenomena are at least as important as electrical
and that there are computers where the storage system is mainly acoustic.
Hence the use of electricity is simply “a very superficial similarity”.
> TURING:
> The imitation game could then be played with the machine in question (as B)
> and the mimicking digital computer (as A) and the interrogator would be
> unable to distinguish them. Of course the digital computer must have an
> adequate storage capacity as well as working sufficiently fast.
Yusuf L:
Here Turing is saying if we have a digital computer as B and give to it a
table corresponding to the discrete states of machine A, B should be able to
mimic A indistinguishably. This is an argument I agree with but a digital
computer cannot be programmed to mimic the human computer in this way,
because we are not discrete state machines but truly random thus returning
to my earlier point that physiology must have something to do with it.
> TURING:
> Let us fix our attention on one particular digital computer C. Is it true that by
> modifying this computer to have an adequate storage, suitably increasing its
> speed of action, and providing it with an appropriate programme, C can be
> made to play satisfactorily the part of A in the imitation game, the part of B
> being taken by a man?
Yusuf L:
Turing modifies the question, “can machines think?” in light of the
discussions. Personally I find the context of the question as vague as the
first. What exactly is satisfactorily? Is that the five minutes initially
quoted or the forty-five minutes used for the Loebner prize competition? If
it is either or even longer what exactly do we gain by fooling the
interrogator for a time period? Passing the TT requires a lifetime capacity and lifelong
indistinguishability, to anyone and everyone. It is only then we can start
to consider the thinking machine. Views of a time frame shown by the Loebner
Prize only encourages people to develop hard coded systems short of a man
standing in a box to impress for a short time.
> TURING:
> I believe that in about fifty years' time it will be possible, to programme
> computers, with a storage capacity of about 109, to make them play the
> imitation game so well that an average interrogator will not have more than
> 70 per cent chance of making the right identification after five minutes of
> questioning.
Yusuf L:
We have computers with even bigger storage capacities today, however we
haven’t developed systems that can play the imitation game successfully.
But a lot advancements have been made. More importantly, is this
introduction of the time constraints. I can’t help but feel that Turing
did intend for the TT to be a game with time an important factor and maybe
the Loebner Prize have only gone about things the way Turing envisaged. It
might just be that due to some strong thinkers extending the pen-pal version
of the Turing test, the Robotic version was created. And that Turing never
really considered the Robotic version or had ideas on this scale.
> TURING:
> The original question, "Can machines think?" I believe to be too meaningless
> to deserve discussion. Nevertheless I believe that at the end of the century
> the use of words and general educated opinion will have altered so much that
> one will be able to speak of machines thinking without expecting to be
> contradicted.
Yusuf L:
If it is such a meaningless topic, why are we discussing it? To say rather
than check whether a machine can think, make it take the TT (imitation test)
and if it is indistinguishable it can think is a good approach but does not
diminish the scientific interest of whether machines can think. If we were
to develop a digital computer that passes the TT, people would still be
interested in whether it can or cannot think. Better yet what if we develop
a system that passes the TT but can’t think?
It hasn’t happened yet. Talking about the capability of a machine to think
is as controversial as ever. Are we as engineers not evolving as quickly as
we should or was Turing hoping that his vision would be adopted without
question?
Turing to then proceeds to consider opinions opposed to his own.
> TURING:
1. > Theological objection: God has given an immortal soul to every man
> and woman, but not to any other animal or to machines. Hence no
> animal or machine can think.
Yusuf L:
This is a theological argument, which I am not equipped to discuss. However,
if God made us in his own image, doesn’t that imply that we should have
his creativity and be able to give souls to the machines we create.
> TURING:
2. > Heads in the Sand Objection: The consequences of machines thinking
> would be too dreadful. Let us hope and believe that they cannot do so.
Yusuf L:
Too trivial to even bother considering.
> TURING:
> 3. The Mathematical Objection: There are a number of results of
> mathematical logic, which can be used to show that there are
> limitations to the powers of discrete-state machines. The best known
> of these results is known as Godel's theorem.
Yusuf L:
Turing acknowledges this argument but suggests it isn’t totally applicable
because if Godel's theorem is to be used we need in addition to have some
means of describing logical systems in terms of machines, and machines in
terms of logical systems.
> TURING:
> 4. The Argument from Consciousness: 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.
Yusuf L:
Perhaps consciousness is not what we should be looking for but that implicit
representation of how we do what we do and are aware of what we are doing.
> TURING
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:
Yusuf L:
Not a very strong argument because even humans have
disabilities and differences but this does not alter the fact that they
can think or intelligent. There are a few more opinions presented in
the report that Turing discusses and attempts to reduce their
credibility.
> TURING:
> But what can we say in the meantime? What steps should be taken now if
> the experiment is to be successful?
Yusuf L:
Here Turing suggests machine learning as a method for developing computers
that would be able to pass the TT. He explains it further by analysing the
adult mind as follows:
> TURING:
> In the process of trying to imitate an adult human mind we are bound to think
> a good deal about the process which has brought it to the state that it is in.
> We may notice three components.
> (a) The initial state of the mind, say at birth, (b) The education to which it
> has been subjected, (c) Other experience, not to be described as education,
> to which it has been subjected.
Yusuf L:
A great idea for developing advanced computers that can move towards
thinking. However, the computer that has been taught would probably only be
equivalent to a pet. Because digital computers as described by Turing might
not be capable. Sensory-motor features might and most probably will be
required. Secondly, learning introduces problems like the credit/blame
assignment and frame problems. I like the idea of taking the development in
stages, I believe that trying to actually develop a system indistinguishable
from a 2yr old is a complex enough task and that we should try to develop
smaller components or machines indistinguishable from less complex life
forms and work our way up. Finally, just as it is difficult to predict what
will be learnt in a human from a lesson or experience so would it be for a
machine if at all.
Turing approached a very complex discussion with an ideal however he left a
lot of his ideas open to misinterpretation. I also believe that he probably
didn’t realise the impact his paper would have on AI as a whole and
probably didn’t even see the genius in some of his ideas and what he said
until others started interpreting them.
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