LAST LECTURE

Functionalism

Functionalism in philosophy of mind is the view that mental states should be identified with and differentiated in terms of functional roles.

A function (as in mathematics) relates inputs to outputs. (e.g. multiplication vs. addition)

A functional role would determine a specific kind of function.

Functional Concepts (1)

Part of FUNCTIONALISM is conceptual.

In a ‘stuff’ concept, what a thing is and what it does is a matter of the nature of the stuff. To be water is to be liquid and wet. To be wood is to be…, to be a sheep is to be… .

Most ‘STUFF’ concepts are the concepts of certain kinds in nature (or ‘natural kinds’).

Functional Concepts (2)

A functional concept identifies what a thing IS with what it does.

To be a knife, is to be a thing that cutsTo be money, is to be the kind of thing that

permits economic exchangeTo be an umpire, is to be the person who

adjudicates events in a baseball game.To be a chess queen, is to be a piece that

moves and captures in a specified manner.

Functional Concepts (3)

If we say that a mental state is a functional kind, then we say that to be “in pain” is to be in that state that relates injury to behaviors of type T.

What the mental states have in common is the functional profile of relating input to output. If two functional states relate the same inputs to the same outputs then they are the same function.

Examples…

Two word processing programs will have different computer code, but will perform the same work. Same function different realization.

A Calculator and an abacus will both perform simple mathematical calculations, but one is digital and one is analog.

A digital clock and a wind-up cuckoo clock both keep time, etc.

Same function different form…

Function and Multiple Realization

One of the primary reasons people entertain functionalism about mental states is that functional states are multiply realizable.

Recall: MR was a problem for identity theory. Now it is a virtue of Functionalism.

Functionalism Review

1) Functionalism in philosophy of mind is the view that mental states should be identified with and differentiated in terms of functional roles.

2) A function (as in mathematics) relates inputs to outputs. (e.g. multiplication vs. addition). A functional role would determine a specific kind of function.

3) Functional Concepts define things relative to functions4) Functions are multiply realizable.

According to Functionalism…To be in a mental state S is to have your brain realize a

functional state F.

Two models

Behavioral Model Mind Plays a role(?) model

StimuliStimuli

Behavior Behavior

ConditionedResponses

MENTALEVENTS

Not observable Observable

WHY ISN’T FUNCTIONALISM JUST A VERSION OF BEHAVIORISM

Determines Type

More Models

Functional Model Mind Plays a role(?) model

StimuliStimuli

Behavior Behavior

Functional State

MENTALEVENTS

Not observable Observable

…Because the functional role determines what the state is, not the input/output pair

…that means, e.g., pain and fake-pain are different states…

Hardware – Software Analogy

According to one version of Functionalism

The brain is like a computer and your mental states are like programs that run on that computer. The same computer can run different programs at different times and the same (or similar) programs can be run on different computers.

Objection to Functionalism

Block’s Liberalism Objection:

If having a functional organization F is sufficient for being in mental state M, then anything which realizes F will be M.

So if F1 is “being in love with Laura Bush”, and a crashing wave contains water molecules that realize F1, then the wave loves Laura Bush.

See the unhappy rainbow?

The Qualia Objection

Similar to the Conscious experience argument for dualism.1) Conscious experience contains more information than the

physical facts provide: ‘What its like to X’ or Qualia2) Qualia has no functional role.3) If functionalism is true there is no requirement that functional

states have associated qualia. Thus mental states need not have qualia. (Qualia Zombies)

4) But the presence of qualia is paradigmatic of consciousness. And consciousness is a mental state.-----------------------------------------------------------------

5) Therefore, functionalism is not a complete account of mental states.

Functionalism and Artificial Intelligence (AI)

Non-Biological Realization:

If a functional state can be realized outside of a biological system, then can we build a system (e.g. in a computer) that has REAL mental states?

Such a system would be a form of Artificial Intelligence. (AI)

Types of AI

There are two conceptions of AI

Strong AI – non-biological systems can realize real mental states.

Weak AI – non-biological systems can only simulate mental states. We can learn about the mind by studying these systems, but they are not real minds.

Is Simulation just Simulation?

Simulated Weather Simulated Sunlight Simulated Flight Simulated Clocks

What kind of simulation is an AI system?

Can Machines (really) Think: The Turing Test

In a famous 1950 paper Philosopher-Mathematician Alan Turing asked:

“Can a machine think?”

To answer the question he proposed an experiement called the ‘Imitation Game’ or (later) Turing Test

Turing and Turing Machines

ALAN M. TURING

He developed a way to resolve complex mathematical problems using imaginary machines (digital computers)

One kind of Turing Machine:

A Turing “Bombe” code-breaker

A Basic Turing Machine Diagram

INPUT OUTPUT

MEMORY

PROCESSOR

One way to make a TM is to write a program that wins the Turing Test

Turing Machines are MRA Turing machine can be diagrammed …or built of metal …or of blueberry muffins and frosting.

…AND STILL BE A Turing Machine

The Imitation Game…

A Man in a chat-room pretends to be a woman

A woman in a chat-room answers questions as she normally would

You may ask any question you want for 15 minutes via computer. If you cannot tell who the real woman is, then the man wins. He is indistinguishable from the woman.

The Turing Test: A computer tries to imitate a human…

COMPUTER

WHICH IS WHICH? IF YOU CAN’T TELL, IS THERE A DIFFERENCE?

Try the Turing Test on your friends…

How do you know that they can think?

Imagine that you could only talk to them in a chat room or in some other setting where behavior was not a factor.

You would ask questions and judge on the basis of answers.

Objections to Turing’s Claim

Turing doesn’t answer his own question. He gives a test, and suggests that computers will be able to pass it at some point

Here are some traditional objections:1) The Soul: you must have a soul to think.2) Originality: Computers must obey programs so they

cannot do anything original.3) Humor: Thinking yields humor, machines don’t make

jokes.4) Head in the Sand: Oh dear, wouldn’t be awful if they

did think?5) Learning: Machines can’t learn, but thinkers can.

Turing’s Replies…

1) The Soul: you must have a soul to think. -- God could make a thinking machine…2) Originality: Computers must obey programs so they

cannot do anything original.-- Programs could incorporate randomness

3) Humor: Thinking yields humor, machines don’t make jokes.-- Why must thinking and humor coincide?

4) Head in the Sand: Oh dear, wouldn’t be awful if they did think?-- A worry is not an objection.

5) Learning: Machines can’t learn, but thinkers can.-- Complex machines can acquire new inputs from the environment and previous processing.

Searle’s Chinese Room

The best known objection to strong AI is John Searle’s CHINESE ROOM objection.

The objection is this:

If a system can pass the Turing Test then it understands language, but in a Chinese Room there is no part that understands language. So at best a TT simulates thinking.

The Chinese Room

INPUT OUTPUT

MEMORY

PROCESSOR