3.4 Foundations of Cognitive Brain Research
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What is intelligence?
Learning goals:
- What is intelligence?
- How do we decide that someone is intelligent?
- How do we measure intelligence?
- Can machines be intelligent?
- How do we determine if they are?
- Can animals be intelligent?
- How do we determine if they are?
The Turing Test (2019) - Oppy & Dowe
The Turing Test was a proposal made by Turing in 1950 as a way of dealing with the question
whether machines can think.
Descartes
Wrote about the resemblance between machines and humans but also had a few points as to why
machines are not real humans.
1. Machines could never use words, or put together signs, as we do in order to declare our
thoughts to others. It is inconceivable that a mere machine could produce different
arrangements of words, so as to give an appropriately meaningful answer to whatever is said
in its presence.
2. Even though some machines might do some things as well as we do them, or perhaps even
better, they would inevitably fail in others, which would reveal that they are acting not from
understanding, but only from the disposition of their organs. It is for all practical purposes
impossible for a machine to have enough different organs to make it act in all the
contingencies of life in the way in which our reason makes us act.
It seems that Descartes gives a negative answer to the questions whether machines can think, and
this negative answer seems tied to his confidence that no machine could pass the Turing test.
It does seem that Descartes would have agreed that the Turing test would be a good test of his
confident assumption that there cannot be thinking machines.
Blockhead (Ned Block)
Ned Block created Blockhead and contradicted the Turing Test.
Blockhead was a robot that could use words and behave as human, but did not have an IQ or mind.
Hoe doesn’t think or understand, everything he does is programmed → Thus contradicting the Turing
Test.
Blockhead is programmed so that it seems like a continuous state machine, but it is actually a discrete
state machine.
Description of the Turing test
Suppose that we have a person, a machine, and an interrogator. The interrogator is in a room
separated from the other person and the machine. The object of the game is for the interrogator to
determine which of the other two is the person, and which is the machine. The interrogator knows the
other person and the machine by the labels X and Y - but, at least at the beginning of the game, does
not know which of the other person and the machine is X - and at the end of the game the interrogator
has to say whether X is the machine or the person.
The interrogator is allowed to put questions to the person and the machine of the following kind: “ Will
X please tell me whether X plays chess?” Whichever of the machine and the other person is X must
answer questions that are addressed to X.
, 2
The object of the machine is to cause the interrogator to mistakenly conclude that the machine is the
other person; the object of the other person is to try to help the interrogator to correctly identify the
machine.
Turing believed that in 50 years it would be possible to program computers that would play the game
so well, that an average interrogator will not have more than 70% chance of making the right
identification after 5 minutes of questioning.
There are two kinds of questions that can be raised about this prediction:
- Empirical questions (is it true that we can now play this game so well)
- Conceptual questions (if the above is true, can we conclude that the machine exhibits some
level of intelligence)
Turing test competitions:
- The computer program Eugene Goostman (2014) had fooled 33% of the judges in the Turing
test competition, so it was claimed that it had passed the Turing test.
- There have been other one-off competitions in which similar results have been
achieved:
- PC Therapist (50% of judges)
- Cleverbot
But: In all three of these cases, the size of the trial was very small, and the result was not reliably
projectible
→ In no case were there strong grounds for holding that an average interrogator had no more than a
70% chance of making the right determination about the relevant program after 5 minutes of
questioning.
Some people say that the test is chauvinistic: it only recognizes intelligence in things that are able to
sustain a conversation with us → something is not intelligent when it can’t.
- However, this charge is besides the point. Turing claims that if something can carry out a
conversation with us, then we have good grounds to suppose that it has intelligence of the
kind that we possess. It does not claim that ONLY something that can carry out a
conversation with us can possess the kind of intelligence that we have.
Other people say that the test is not demanding enough: some unintelligent programs are able to
show intelligence and fool observers.
- But in the Turing test, just fooling an observer is not enough. The machine has to survive a
questioning by an interrogator who knows that one of the other two participants in the
conversation is a machine. The machine has to survive an interrogation with a high degree of
success over a repeated number of trials.
Another contentious aspect of Turing’s paper concerns his restriction of the discussion to the case of
digital computers.
- On the one hand, it seems clear that this restriction is really only significant for the prediction
that Turing makes about how things will be in the year 2000, and not for the details of the test
itself. Indeed, if the test is good, then it would be a good test for all kinds of entities, including
animals, aliens, and analog computers → If these entities pass the Turing test, then there will
be as much reason to think that these things exhibit
intelligence as there is reason to think that digital
computers that pass the test exhibit intelligence.
- On the other hand, it is actually a highly controversial question whether “thinking machines”
would have to be digital computers, and it is also a controversial question whether Turing
himself assumed that this would be the case.
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Objections regarding the Turing test
Turing discusses potential objections. In some cases, the counter-arguments to these objections are
also provided by Turing.
- Theological objection: Dualists believe that thinking is a function of a non-material, separately
existing substance that somehow combines with the body to make a person. Just making the
body (or a machine) will never be enough to create thought (or intelligence). You can go even
further and say that a soul comes from God, and it is not possible to put a soul in a machine.
- Criticism: In general there is much criticism on dualism and theism. And even if God
exists, machines could think if God would put the soul in the machine, and there is no
reason to think that God couldn’t to this.
- The “heads in the sand” objection: If machines can think, we are not superior anymore. If
machines can think, they could become better thinkers than we are, and we could be
supplanted by machines. We might even be dominated by machines. This is not so much an
argument as to why machines wouldn’t be able to think, but an argument about the fears that
go along with thinking machines.
- Criticism: This is not an argument as to why machines can’t think. Someone who
takes these worries seriously might well think that we have reasons for giving up on
the project of attempting to construct thinking machines. However, it would be a major
task to determine whether there are any good reasons for taking these worries
seriously.
- The mathematical objection: They say that within a formal system that is strong enough, there
are a class of true statements that can be expressed, but not proven within the system →
Such a system is subject to the Lucas-Penrose constraint. It is constrained from being able to
prove a class of true statements expressible within the system. In the context of the Turing
test, it implies that unanswerable questions exist. These questions, however, are only a
concern if humans can answer them.
- If humans are subject to the Lucas-Penrose constraint, then the constraint does not
provide any basis for distinguishing humans from digital computers. If humans are
free from the Lucas-Penrose constraint, then it follows that digital computers may fail
the Turing test, and thus, it seems, cannot think.
- There remains the question as to whether being free from the constraint is necessary
for the capacity to think → Maybe it is possible that an entity which can think would
fail the Turing test.
- Argument from consciousness: You can only be sure that a machine can think, if you are the
machine itself and experience thinking. Perhaps self-consciousness is necessary to think (so
for example: if you write something, you know that you are writing instead of just doing it
without knowing what you’re doing). It is a mistake to take a narrow view of the mind → to
suppose that there could be a believing intellect divorced from the kinds of desires and
emotions that play such a central role in the generation of human behavior (there is more to
intelligence than just reasoning and logic).
- Turing:
- against the solipsistic line of thought, we have as much reason to assume
that a machine thinks as we have to assume that other people think
→ the only person you can be sure of that can think, is yourself.
- Even a machine with a digital computing ‘brain’ can have the full range of
mental states that can be enjoyed by adult human beings.
- Argument from various disabilities: A machine can never be kind, resourceful, beautiful,
friendly, have initiative, a sense of humor, tell right from wrong, make mistakes, fall in love,
enjoy strawberries and cream, make someone fall in love with one, learn from experience,
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