Transcript Computing Machinery and Intelligence Written by A. M. Turing Summarized by Kim Kyoung-Soo

Computing Machinery and
Intelligence
Written by A. M. Turing
Summarized by Kim Kyoung-Soo
The Imitation Game
The Question: “Can machines think?”
Imitation game: the new form of the problem
Played with three people, a man(A), a woman(B),
and an interrogator(C)
The interrogator is to determine which of the
other two is the man/woman
The question “What will happen when a machine
takes the part of A in this game” replace the
original question, “Can machines think?”
Critique of the New Problem
“Is the new question a worthy one to
investigate?”
Drawing a fairly sharp line between the physical
and the intellectual capacities of a man
Q ‘n A method excludes the irrelevant disabilities
Are the odds weighted too heavily against the
machine?
At least, if a machine can, we need not troubled by that.
The Machine Concerned in the
Game
To specify what the word “machine” means
Only permit digital computers to take part in our
game
Ask whether there are imaginable computers
which would do well
The Human Computer
A definition for a “thinking machine”
The machines are intended to carry out any
operations which could be done by a “human
computer”.
The human computer
is supposed to be following fixed rules
has the rules supplied in a book
has an unlimited supply of paper on which he
does his calculations
Digital Computer
To avoid danger of circularity of argument, we
give an outline of the digital computer, using
the explanation of the human computer.
Regarded as consisting of three parts
(i) Store
(ii) Executive unit
(iii) Control
Three Parts of a Digital Computer
The store
a store of information: correspond to the human
computer’s paper or the book of rules(table of
instructions)
The executive unit
the part which carries out the various individual
operations involved in a calculation
The control
the part which sees that the instructions are
obeyed correctly and in the right order
The Information in the Store
Usually broken into packets of moderately
small size, e.g. ten decimal digits
“Add the number stored in position 6809 to that in
4302 and put the result back into the latter storage
position” ===> ‘6809430217’
“If position 4505 contains 0 obey next the instruction
stored in 6707, otherwise continue straight on.”
Constructing instruction tables is described as
“programming”
Some Related Issues About D.C.
Digital computer with a random element
“Throw a die and put the resulting number into
store 1000”
Sometimes such a machine is described as having
free will.
Infinitive capacity computers
There is no theoretical difficulty in the idea of a
computer with an unlimited store - we can imagine
more and more being added as required.
Discrete-State Machine
The digital computers may be classified
amongst the “discrete-state machines.”
The discrete-state machine
Moves by sudden jumps or clicks from one quite
definite state to another
States are sufficiently different for the possibility
of confusion
Given the initial state of the machine and the
input signals, it is always possible to predict all
future states
Discrete-State Machine(cont’d)
An example of a D-S machine
Last State
q1 q2 q3
Input
i0
i1
q2 q3 q1
q1 q2 q3
q1, q2, q3: internal state of the machine
i0, i1: input signal
output signal(light):
State q1 q2 q3
Output o0 o0 o1
University of Digital Computers
Universal machine
A digital computer can mimic the discrete-state
machine’s calculation(to predict what it will do).
This special property of digital computers is
described by saying that they are universal
machines.
The main question reconsideration
see page 19.(CT)
Contrary Views on the Main
Question
The theological objection
the “Heads in the Sand” objection
The mathematical objection
The argument from consciousness
Arguments from various disabilities
Lady Lovelace’s objection
Argument from continuity in the nervous system
The argument from informality of behaviour
The argument from extrasensory perception
The Theological Objection
“Thinking is a function of man’s immortal
soul. Hence no animal or machine can think.”
The argument quoted above implies a serious
restriction of the omnipotence of the Almighty.
We might expect that He would only exercise this
power in conjunction with a mutation which
provided the elephant with an appropriately
improved brain to minister to the needs of this soul.
The “Heads in the Sand” Objection
“The consequences of machines thinking
would be too dreadful. Let us hope and believe
that they cannot do so.”
We like to believe that Man is in some subtle way
superior to the rest of creation.
This argument is sufficiently substantial to require
refutation. Consolation would be more appropriate:
perhaps this should be sought in the transmigration
of souls.
The Mathematical Objection
A number of results of mathematical logic
shows that there are limitations to the powers
of discrete-state machines.
Ex. Goedel’s theorem(1931)
In any sufficiently powerful logical system, statements
can be formulated which can neither be proved ore
disproved within the system, unless possibly the system
itself is inconsistent.
It has only been stated that no such limitations
apply to the human intellect.
The Argument from Consciousness
“A machine can only write it but doesn’t know
that it had written it.”
It is in fact the solipsist point of view.
The only way by which one could be sure that a
machine thinks is to be the machine and to feel
oneself thinking.
Likewise according to this view the only way to
know that a man thinks is to be that particular
man.
Cf. viva voce game
Arguments from Various Disabilities
“You will never be able to make a machine to
do X”
Be kind, resourceful, make mistakes, enjoy
strawberry and cream, be the subject of its own
thought, ……
They are mostly founded on the principle of
scientific induction - The machines a man has seen
are ugly, designed for a very limited purpose,….
Lady Lovelace’s Objection
Comes from a memoir by Lady Lovelace(1842)
“The Analytical Engine has no pretension to
originate anything. It can do whatever we
know how to order it to perform”
Hartree(1949): “This does not imply that it may
not be possible to construct electronic equipment
which will ‘think for itself’, which would serve as
a basis for ‘learning’.
Argument from Continuity in the
Nervous System
“The nervous system is certainly not a
discrete-state machine(continuous system). So
a D-S machine cannot mimic the behavior of
the nervous system.”
A digital computer would be quite capable of
giving the right sort of answer, although it cannot
predict exactly what a continuous system answers
to a problem.
Ex. Differential analyser
The Argument from Informality of
Behavior
“It is not possible to produce a set of rules
purporting to describe what a man should do
in every conceivable set of circumstances.”
“Man has no definite set of rules of conduct
by which he regulated his life”
We cannot convince ourselves of the absence of
complete laws of behavior as of complete rules of
conduct
Learning Machines
Our problem is to find out how to programme
these machines to play the game.
Three components of the process
The initial state of the mind, say at birth
The education to which it has been sujected
Other experience
Instead of trying to produce a programme to
simulate the adult mind, rather try to produce
one which simulates the child’s
Learning Machines(cont’d)
Punishment and rewards
events which shortly preceded the occurrence of a
punishment signal are unlikely to repeated
a reward signal increased the probability of
repetition of the events
“Unemotional” channels of communication
“Human fallibility” is likely to be omitted in a
rather natural way.
Which Are The Best Ones to Start
With?
Abstract activity like the playing of chess
vs. practical activity such as the best sense
organs that money can buy, understanding and
speaking English, etc.