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Article 4418 of comp.ai.philosophy:
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>From: santas@inf.ethz.ch (Philip Santas)
Newsgroups: comp.ai.philosophy
Subject: Re: Definition of understanding
Message-ID: <1992Mar11.230114.29498@neptune.inf.ethz.ch>
Date: 11 Mar 92 23:01:14 GMT
References: <1992Mar10.171755.7458@psych.toronto.edu> <1992Mar11.122705.22342@neptune.inf.ethz.ch> <1992Mar11.185921.10347@psych.toronto.edu>
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In article <1992Mar11.185921.10347@psych.toronto.edu> michael@psych.toronto.edu (Michael Gemar) writes:
>santas@inf.ethz.ch (Philip Santas) writes:
>>
>>michael@psych.toronto.edu (Michael Gemar) writes:
>>>
>>>PE = 1/2 k x^2
>>>
>>>where PE = potential energy
>>>       k = spring constant
>>>       x = displacement from equilibrium
>>>
>>>How do you give definitions that have semantic content to a computer?
>>>How does it know that when you respond to the request "Please input
>>>the capacitance constant => " that you are talking about capacitance,
>>>and not number of cars?  The problem of generating "definitions" with
>>>semantic content for a computer *is* the central problem under discussion.
>>
>>You can do type checking even statically in this example:
>>
>>  PE GivePE(Distance displacementFromEquilibrium)
>>          {
>>           Distance x = displacementFromEquilibrium;
>>           SpringConstantType k = SpringConstant;    // this is global variable
>>           return (1/2) * k * power(x,2);
>>          };
>>
>>Relevant things you can do for capacitances, by changing the type
>>of the argument displacementFromEquilibrium.
>
>This does *not* ground the meaning of these terms.  How do these variables
>know that the numbers input are spring constant and displacement, rather
>than capacitance and potential.  Merely typing

Because of their type; there is a type differentiation.

>Distance x = displacmentFromEquilibrium
>
>does not tell the computer what "distance" and "displacement from equilibrium"
>*is*!  I could have just as easily typed:
>
>Qaatlus x = GwornsBleebArack
>
>and the program would *still* compute *both* Potential *and* electrostatic
>energy.

Notice that there are many human languages and you can say the same thing 
with differnt words and syntax. What I do not understand is how can a 
you calculate two irrelevant things by evaluating just one function.

The computer in my example has an internal representation for the type
Distance. This representation can be enriched for the purposes of more
complex tasks. What is YOUR internal representation of Distance?
What do you understand under the terms 'Distance from Sun to Star A' or
'speed of light'? 

>>>         But I do not see a way of providing variable definitions that would
>>>"clear things up" from the point of view of the computer.
>>
>>Notice that EVEN languages like C++ have such abilities...
>
>C++ may have the ability to distinguish between different variables.  It
>does *not* have the ability to provide semantics for those variables.

In many computer languages you have the ability to define data types,
relationships among them, rules, constraints and many other elements.

Are you aware of the semantical instantiation in a human brain?
If yes why is it impossible to implement this in a machine?
If no why do you argue against the abilities of these building blocks
for modelling semantics?

Philip Santas
 
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