Comments about the book ""Computer Power and Human Reason"" by Joseph Weizenbaum
This document contains comments about the book: "Computer Power and Human Reason" by Joseph Weizenbaum. W.H.Freemann and company 1976
 The text in italics is copied from that url
 Immediate followed by some comments
In the last paragraph I explain my own opinion.
Contents
Reflection
1. .
























2. Where the power of the computer comes from








page 64

Turing's thesis tells us that we can realize, as a computer program, any procedure that could "naturally" be called an effective procedure.

To computer program requires a purpose. A purpose is a description in the form of an algorithm.
The purpose is to calculate a maximum and the algorithm tells you how to calculate this maximum. The algorithm is a description of a sequence of logical operations.

Therefore, whenever we believe we understand a phenomenon in terms of knowing its behaviour rules, we ought to be able to express our understanding in the form of a computer program.

This is a very important sentence. The problem is what exactly are these "behaviour rules".
If this behaviour rules can be expressed as an algorithm, in a sequence of logical statements, then there is a basis for computation.
If this is not the case than any computation will fail.
For example a "behaviour rules" like: "When I'm hungry, I need food" is too simple.

For now, we need note only that the defect in our understanding can take two forms.

Okay,

First, although our theory may be on the whole correct, it may contain an error in detail.

I expect our theory means: All our understanding to solve a physical problem
In general when our theory contains any error it is wrong.

We wrongly assert, for example, that if this and that is true, then soandso follows.
That is a large error.

page 65

It follows the logic we have given it.

Correct.

That logic may lead to very different consequences than do mental processes contaminated by wishes to reach certain outcomes.

That sentence is too complicated. The issue is that a computer follows the logic based on what we understand. That understanding can be wrong.

Indeed one of the most cogent reasons for using computers is to expose holes in our thinking.

That is not its primary task.



But our predictive power, great and reliable as it may be, may rest on intuitions that we are simply unable to adequately explicate.

That can be easily the case. For example: No one knows how to describe the physics involved in the behaviour of weather (in the future). As such it is very difficult to predict the weather.

Yet we may be driven to force our ideas into a formal mold anyway

As you wish.

A computer program based on a formal system so derived is certain to misbehave.

The computer program does not misbehave. It will perform its tasks as requested. The final result (solution of the problem) will be wrong.





It is not always clear which defect one is confronted with when a computer, one has programmed, misbehaves.

Generally speaking computers do not misbehave. They always (with certain exceptions) give the same result. The problem is in the computer program (which is an image of physical problem you try to solve)

We now ask whether the universality of computers implies that they can "do anything"

That question is to general.

The answer to that question is "No"

Ofcourse.

First, there are certain questions that can be asked and for which it can be proved that no answers can be produced by any effective procedure whatever.

There are many physical problems for which no (realistic) solution exists.

We may, for example, be interested to know whether some machine we have designed, say, our adding machine, will halt once started with a particular dat set.

The first question to answer is: what is meant with "halt"
In general there are two issues:
 Does the computer always stop and find an answer.
 Is the answer correct.
The only way to demonstrate this is: try the adding machine.
First try the example 2+3=5 : X11X0X111X which should give the result 000011111X
Next try as many different combinations as possible.
The general answer is "No"

It would be convenient if we had a testing machine which could, for any machine and any data set appropiate to it, tell us whether that machine operating on the given data set would ever halt.

The question is much simpler: Will each given data set always "halt"
IMO the answer is "No". And when it stops the answer can be wrong.










3. How compuers work
























4. Science and the compulsive programmer
























Reflection 1.
Reflection 2
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Created: 1 October 2018
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