Re: Babbage/Menabrea: Analytical Engine

From: HARNAD Stevan (
Date: Wed Feb 21 2001 - 18:19:44 GMT

Francis-Oladipo Marinho ( ) wrote:
> <
> <
> Marinho:
> if the machine is to live up to its name of being
> able to perform any function or calculation...
> ...the Analytical Engine....
> was meant to solve the problem of dealing with absolutely any
> mathematical problem.

Was there a clear idea at the time of what was meant by "able to
perform any function or calculation"? Was this the intuitive or
the formal sense of the Church/Turing Thesis?

And was Babbage's Analytical Engine an approximation to a Universal
Turing Machine?

> Marinho:
> Menabrea... concludes
> that given a machine that can implement the four main arithmetic
> functions, i.e. addition, subtraction, multiplication and division,
> any other problem could be solved. This slightly contrasted with his
> earlier comment in the paper about Pascal's machine being less powerful
> as it only implemented the four main arithmetic operations.

But what is the truth?

> Marinho:
> Menabrea then proceeds to show how a machine would eliminate its need
> for human intervention

What was the motivation for eliminating the need for human
intervention, practical, or something deeper?

> Marinho:
> The idea that a machine could perform any given calculatiion implied
> that it would have to be able to cater for analytic problems as well as
> numerical ones

What is the difference between analytic and numeric problems, and how
is it related to the nature of computation?

> > the interpretation of formulae and
> > of results is beyond its province, unless indeed this very
> > interpretation be itself susceptible of expression by means of the
> > symbols which the machine employs. Thus, although it is not
> > itself the being that reflects, it may yet be considered as the
> > being which executes the conceptions of intelligence

What does this mean?

> Marinho:
> In my opinion, his conclusion about the machine that would perform
> calculations based on rules it was given was correct to a degree. He
> suggested that such a machine was not necessarily intelligent, on the
> assumption that intelligence is displayed by reflection.

What does "reflection" mean?

> He goes
> further to say it executes conceptions of intelligence. Surely, if the
> beliefs of Alan Turing and Alonzo Church are observed, then if a
> machine can execute the concepts of intelligence, it should also be
> able to be considered intelligent.

What does "executes conceptions of intelligence" mean? Does it just
mean "do what intelligent systems can do"?

> Touching again on the area of intelligence, Menabrea's opinion is that
> little intelligence is required for such a machine as it is only
> implementing operations that are given to it, in other words an
> algorithm. So it speeds up calculations and does not require prior
> training. Some would argue that humans implement algorithms too and as
> they were learnt by humans who are considered intelligent, why should
> the machine be considered to have lower intelligence since it also
> learnt the algorithm.

Yes, this is the question, isn't it...

What is the answer?

Stevan Harnad

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