If A Tree Casts A Shadow, Is It Telling The Time?
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If a Tree Casts a Shadow, is it Telling the Time? Russ Abbott California State University, Los Angeles
One day, Mara, the Buddhist god of ignorance and evil, was traveling through the villages of India with his attendants. He saw a man doing walking meditation. The man’s face was lit up in wonder. He had just discovered something on the ground in front of him. Mara's attendants asked what the man had discovered. 10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
2
Humans: smart enough to have ideas; foolish enough to believe them. “A piece of truth,” Mara replied. “Doesn't this bother you when someone finds a piece of the truth, O evil one?” his attendants asked. “No,” Mara replied. “Right after this they usually make a belief out of it.” -- Christina Feldman and Jack Kornfield, in “Stories of the Spirit, Stories of the Heart,” from Everyday Mind, Jean Smith (ed) . 10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
3
Preview of issues and answers
What is computation?
What is the relationship between ideas and programs?
Programs are how we understand rigorous thought to be expressed.
When can a natural process be used for computation?
Physical processes are computation when we treat them as externalized thought.
Computation involves the playing out of fixed natural processes against a contingent environment.
How do we think about the relationship between ourselves as rational beings and the environment?
The agent-based model of computation is the right way to think about our interaction with an environment. • But we do not yet understand multi-scalar environments.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
4
Is Google reading my email? Answer from the Gmail.com FAQ
Google computers scan the text of Gmail messages in order to filter spam and detect viruses, just as all major webmail services do. Google also uses this scanning technology to deliver targeted text ads and other related information. The process is completely automated and involves no humans. [Emphasis added.]
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
5
What do we really care about?
It’s what goes on in the mind of human beings that matters to you.
Most people find it reassuring that
although Google’s computers may be reading their email no human beings are.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
6
We care about meaning — A computer? With a mind? Nonsense. So you don’t care if computers read your email.
which has as something to do with an idea forming in a mind.
Not the same as formal semantics, i.e., mapping syntax to models.
Most people don’t believe it makes sense to say that an idea has formed in the mind of a computer
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
7
Berkeley’s question If a tree falls in a forest with no one around to hear it, does it make a sound? His answer: yes because God is there to hear it.
Our answer (David Chalmers: the hard problem of AI, subjective experience)
One must distinguish between physical events and subjective experience. If a tree falls in a forest, it generates (what we call) sound waves. But if no being has a subjective experience of sound, no sound will be heard/experienced. • I agree with Chalmers that we have no idea how to think about subjective experience and connect it to everything else.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
8
Berkeley’s question extended
If a tree grows in a forest with no one aware of it, is it instantiating the idea of a tree?
Our answer (the same as before)
The idea of a tree exists only as subjective experience. Even if the idea of a tree is exactly the right way to describe that particular aspect of nature, that idea exists only as an idea, and it exists only in the mind of someone who is thinking it. Ideas exist only as subjective experience.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
9
Computations are ideas When a computer runs is it computing? A computer is computing only when it is understood to be performing some externalized mental activity. Otherwise, it’s just an arena within which electrons are moving about.
Like ideas, computations are also mental events.
But they are mental events that we have externalized in a way that allow us to use physical processes to perform them.
When a tree grows rings, it just grows rings.
When we use tree-ring growth as a way to count years—to help us work with ideas such as “a year”— then we can say that the tree has performed an computation. 10/18/08 (unconventional) Humans: smart enough to have ideas; foolish enough to believe them. 10
Thought tools
A thought tool is a physical device/object that helps us externalize and work with our thoughts. We have developed thought tools in a number of domains: time (shadows, clocks, etc.), numbers (abaci, etc.), space (straight edge, compass), diagrams (Tree of Porphyry), random wisdom (Lull’s logic machine) Thought tools differ in kind from scientific instruments — microscopes, telescopes, other instruments of observation.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
11
Computers and thought tools
Every computer application is a thought tool
Its conceptual model represents the thoughts that are being externalized.
Domain specific languages formalize how we think about those domains. General purpose programming languages are languages for building thought tools—and hence are meta thought tools. The most sophisticated work in this area involves declarative and other advanced programming language constructs, meta-notations, semantic and ontology languages, etc.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
12
Defining Computation physically A series of rule governed state transitions
whose rules can be altered.
Eliasmith, Dictionary of the Philosophy of Mind, http://philosophy.uwaterloo.ca/MindDict/computation.html.
Presumably he means state transitions of physical elements. Otherwise we start in the mental realm and simply stay there.
Defines computation as something in and
of the world and independent of us, i.e., a natural phenomenon of sorts. We claim this can’t be the case. 10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
13
Defining Computation physically Eliasmith
claims that if you leave out the condition that the rules can be altered every physical system is a computational system, which makes the definition vacuous. Can the transition rules be altered?
They can’t if we suppose that physical processes operate according to unalterable physical laws. You can’t change the laws of physics.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
14
Defining Computation physically What do we do when we create a
computation?
We alter the environment within which the laws of physics operate.
When we load a program into a computer,
we are altering the environment within which the CPU (or some virtual machine) operates. 10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
15
Defining Computation physically A physical process is just what it is, a
process. When we put objects on a balance scale, is it performing a computation?
We are altering the environment within which the balance scale maps states to states.
But a balance scale is performing a
computation only if we are using it for this purpose.
Rather than as a designer setting for flower pots.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
16
Computation is externalized thought (again)
For almost all processes, how the process proceeds depends on environmental contingencies.
When we control (or interpret) the contingencies so that we can use the resulting state transitions to work with our own thoughts, then the process is a computation.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
17
Eliminating the von Neumann middleman
Computing involves configuring environmental contingencies within which natural processes will play themselves out: non-algorithmic computing
Conventional computation (with real computers) is a (very) constrained form of unconventional computation.
We use conventional computation to simulate unconventional computation.
A goal of this conference is to eliminate the von Neumann middle man—to find ways to externalize our thoughts by mapping them more directly onto the forces of nature. 10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
18
Turing Machines as computation? Why can’t we look to Turing Machines (and
their equivalents) for a definition of computation defined independently of thought? Turing Machines, recursive functions, and their equivalents rely on the notions of symbols and symbol manipulation, which are fundamentally mental constructs. 10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
19
It’s not the function; it’s the process
Turing Machines and equivalent models are all defined constructively, i.e., in terms of the operations one may perform when constructing a computational procedure.
Computability theory takes this generic class of software and applies it to the task of computing functions.
A program in one model can be constructively converted to be a program in another. Turing Machines and equivalent models are equivalent as programming languages: they define the same computations.
But this step isn’t necessary.
What’s important about the Church-Turing Thesis is that Turing Machines, etc. characterize a fundamental mode of thought: to be considered externalizable a thought process must, at least in principle, be expressible as a software.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
20
It’s not the function; it’s the process
Turing Machines and equivalent models are all defined constructively, i.e., in terms of the operations one may perform when constructing a computational procedure.
Originally Turing understood his model to be a formalization of what we mean by an “effective procedure.” Computability theory takes this generic class of software and applies it to the task of computing functions.
A program in one model can be constructively converted to be a program in another. Turing Machines and equivalent models are equivalent as programming languages: they define the same computations.
But this step isn’t necessary.
What’s important about the Church-Turing Thesis is that Turing Machines, etc. characterize a fundamental mode of thought: to be considered an (externalizable) effective procedure a thought process must be expressible as a software.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
21
Wegner’s interactive machines
Wegner claims that his interactive machines (basically agents) are more powerful than Turing Machines. We think that’s the wrong question. Wegner implicitly takes the same stance that we take above: to distinguish between the programs one can write and the functions those programs can compute. The programs are the same; they are “more powerful” only because they are open with respect to information flow.
10/18/08
Iterative PD (open) is more successful than one-shot PD (closed). Humans: smart enough to have ideas; foolish enough to believe them.
22
We think of ourselves as agents
An environmentally sophisticated agent-based paradigm involves agents, each of which has the computing capability of a Turing machine, situated in an environment that reveals itself reluctantly. Such an agent in a real-world environment is like an Oracle machine, with nature as the oracle. We are still talking about effective procedures. It’s just that the environment within which the procedure operates may change as the procedure proceeds. Real-world, far-from equilibrium agents:
must extract energy from their environment to persist embody software capable of processing information flows from the environment
The agent-based thesis is that this paradigm represents how, at the start of the 21st century, we think about ourselves as rational actors.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
23
One day, Mara, the Buddhist god of ignorance and evil, was traveling through the villages of India with his attendants. He saw a man doing walking meditation. The man’s face was lit up in wonder. He had just discovered something on the ground in front of him. Mara's attendants asked what the man had discovered. 10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
2
Humans: smart enough to have ideas; foolish enough to believe them. “A piece of truth,” Mara replied. “Doesn't this bother you when someone finds a piece of the truth, O evil one?” his attendants asked. “No,” Mara replied. “Right after this they usually make a belief out of it.” -- Christina Feldman and Jack Kornfield, in “Stories of the Spirit, Stories of the Heart,” from Everyday Mind, Jean Smith (ed) . 10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
3
Preview of issues and answers
What is computation?
What is the relationship between ideas and programs?
Programs are how we understand rigorous thought to be expressed.
When can a natural process be used for computation?
Physical processes are computation when we treat them as externalized thought.
Computation involves the playing out of fixed natural processes against a contingent environment.
How do we think about the relationship between ourselves as rational beings and the environment?
The agent-based model of computation is the right way to think about our interaction with an environment. • But we do not yet understand multi-scalar environments.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
4
Is Google reading my email? Answer from the Gmail.com FAQ
Google computers scan the text of Gmail messages in order to filter spam and detect viruses, just as all major webmail services do. Google also uses this scanning technology to deliver targeted text ads and other related information. The process is completely automated and involves no humans. [Emphasis added.]
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
5
What do we really care about?
It’s what goes on in the mind of human beings that matters to you.
Most people find it reassuring that
although Google’s computers may be reading their email no human beings are.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
6
We care about meaning — A computer? With a mind? Nonsense. So you don’t care if computers read your email.
which has as something to do with an idea forming in a mind.
Not the same as formal semantics, i.e., mapping syntax to models.
Most people don’t believe it makes sense to say that an idea has formed in the mind of a computer
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
7
Berkeley’s question If a tree falls in a forest with no one around to hear it, does it make a sound? His answer: yes because God is there to hear it.
Our answer (David Chalmers: the hard problem of AI, subjective experience)
One must distinguish between physical events and subjective experience. If a tree falls in a forest, it generates (what we call) sound waves. But if no being has a subjective experience of sound, no sound will be heard/experienced. • I agree with Chalmers that we have no idea how to think about subjective experience and connect it to everything else.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
8
Berkeley’s question extended
If a tree grows in a forest with no one aware of it, is it instantiating the idea of a tree?
Our answer (the same as before)
The idea of a tree exists only as subjective experience. Even if the idea of a tree is exactly the right way to describe that particular aspect of nature, that idea exists only as an idea, and it exists only in the mind of someone who is thinking it. Ideas exist only as subjective experience.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
9
Computations are ideas When a computer runs is it computing? A computer is computing only when it is understood to be performing some externalized mental activity. Otherwise, it’s just an arena within which electrons are moving about.
Like ideas, computations are also mental events.
But they are mental events that we have externalized in a way that allow us to use physical processes to perform them.
When a tree grows rings, it just grows rings.
When we use tree-ring growth as a way to count years—to help us work with ideas such as “a year”— then we can say that the tree has performed an computation. 10/18/08 (unconventional) Humans: smart enough to have ideas; foolish enough to believe them. 10
Thought tools
A thought tool is a physical device/object that helps us externalize and work with our thoughts. We have developed thought tools in a number of domains: time (shadows, clocks, etc.), numbers (abaci, etc.), space (straight edge, compass), diagrams (Tree of Porphyry), random wisdom (Lull’s logic machine) Thought tools differ in kind from scientific instruments — microscopes, telescopes, other instruments of observation.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
11
Computers and thought tools
Every computer application is a thought tool
Its conceptual model represents the thoughts that are being externalized.
Domain specific languages formalize how we think about those domains. General purpose programming languages are languages for building thought tools—and hence are meta thought tools. The most sophisticated work in this area involves declarative and other advanced programming language constructs, meta-notations, semantic and ontology languages, etc.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
12
Defining Computation physically A series of rule governed state transitions
whose rules can be altered.
Eliasmith, Dictionary of the Philosophy of Mind, http://philosophy.uwaterloo.ca/MindDict/computation.html.
Presumably he means state transitions of physical elements. Otherwise we start in the mental realm and simply stay there.
Defines computation as something in and
of the world and independent of us, i.e., a natural phenomenon of sorts. We claim this can’t be the case. 10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
13
Defining Computation physically Eliasmith
claims that if you leave out the condition that the rules can be altered every physical system is a computational system, which makes the definition vacuous. Can the transition rules be altered?
They can’t if we suppose that physical processes operate according to unalterable physical laws. You can’t change the laws of physics.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
14
Defining Computation physically What do we do when we create a
computation?
We alter the environment within which the laws of physics operate.
When we load a program into a computer,
we are altering the environment within which the CPU (or some virtual machine) operates. 10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
15
Defining Computation physically A physical process is just what it is, a
process. When we put objects on a balance scale, is it performing a computation?
We are altering the environment within which the balance scale maps states to states.
But a balance scale is performing a
computation only if we are using it for this purpose.
Rather than as a designer setting for flower pots.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
16
Computation is externalized thought (again)
For almost all processes, how the process proceeds depends on environmental contingencies.
When we control (or interpret) the contingencies so that we can use the resulting state transitions to work with our own thoughts, then the process is a computation.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
17
Eliminating the von Neumann middleman
Computing involves configuring environmental contingencies within which natural processes will play themselves out: non-algorithmic computing
Conventional computation (with real computers) is a (very) constrained form of unconventional computation.
We use conventional computation to simulate unconventional computation.
A goal of this conference is to eliminate the von Neumann middle man—to find ways to externalize our thoughts by mapping them more directly onto the forces of nature. 10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
18
Turing Machines as computation? Why can’t we look to Turing Machines (and
their equivalents) for a definition of computation defined independently of thought? Turing Machines, recursive functions, and their equivalents rely on the notions of symbols and symbol manipulation, which are fundamentally mental constructs. 10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
19
It’s not the function; it’s the process
Turing Machines and equivalent models are all defined constructively, i.e., in terms of the operations one may perform when constructing a computational procedure.
Computability theory takes this generic class of software and applies it to the task of computing functions.
A program in one model can be constructively converted to be a program in another. Turing Machines and equivalent models are equivalent as programming languages: they define the same computations.
But this step isn’t necessary.
What’s important about the Church-Turing Thesis is that Turing Machines, etc. characterize a fundamental mode of thought: to be considered externalizable a thought process must, at least in principle, be expressible as a software.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
20
It’s not the function; it’s the process
Turing Machines and equivalent models are all defined constructively, i.e., in terms of the operations one may perform when constructing a computational procedure.
Originally Turing understood his model to be a formalization of what we mean by an “effective procedure.” Computability theory takes this generic class of software and applies it to the task of computing functions.
A program in one model can be constructively converted to be a program in another. Turing Machines and equivalent models are equivalent as programming languages: they define the same computations.
But this step isn’t necessary.
What’s important about the Church-Turing Thesis is that Turing Machines, etc. characterize a fundamental mode of thought: to be considered an (externalizable) effective procedure a thought process must be expressible as a software.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
21
Wegner’s interactive machines
Wegner claims that his interactive machines (basically agents) are more powerful than Turing Machines. We think that’s the wrong question. Wegner implicitly takes the same stance that we take above: to distinguish between the programs one can write and the functions those programs can compute. The programs are the same; they are “more powerful” only because they are open with respect to information flow.
10/18/08
Iterative PD (open) is more successful than one-shot PD (closed). Humans: smart enough to have ideas; foolish enough to believe them.
22
We think of ourselves as agents
An environmentally sophisticated agent-based paradigm involves agents, each of which has the computing capability of a Turing machine, situated in an environment that reveals itself reluctantly. Such an agent in a real-world environment is like an Oracle machine, with nature as the oracle. We are still talking about effective procedures. It’s just that the environment within which the procedure operates may change as the procedure proceeds. Real-world, far-from equilibrium agents:
must extract energy from their environment to persist embody software capable of processing information flows from the environment
The agent-based thesis is that this paradigm represents how, at the start of the 21st century, we think about ourselves as rational actors.
10/18/08
Humans: smart enough to have ideas; foolish enough to believe them.
23
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