John Powell
November 7, 2003, 05:32 PM
POWELL:
I would like to bring to your attention what appears to me to be a mistake in your fallacy list in
The Atheism Web
Logic and Fallacies
> http://www.infidels.org/news/atheism/copyright.html
>
> ATHEISM WEB:
>
> The editors of these web documents have attempted to
> verify the accuracy and correctness of the information
> contained in them, as far as is metaphysically possible.
> Mistakes can and do happen, and so far it seems no
> omnipotent beings have intervened to correct them.
> If you use the information in these documents, you do
> so at your own risk.
POWELL:
Although I'm not an Omnibeing, I am hereby notifying you of what I think is a mistake.
> http://www.infidels.org/news/atheism/logic.html
>
> ATHEISM WEB:
>
> Many types of argument exist; we will discuss the
> deductive argument. Deductive arguments are generally
> viewed as the most precise and the most persuasive;
> they provide conclusive proof of their conclusion,
> and are either valid or invalid.
POWELL:
There is no mention anywhere on this page about inductive arguments per se, so the assumption of the reader is that you are discussing only deductive fallacies, not inductive fallacies.
> ATHEISM WEB:
>
> Argumentum ad verecundiam
> The Appeal to Authority uses admiration of a famous
> person to try and win support for an assertion.
> For example:
>
> "Isaac Newton was a genius and he believed in God."
>
> This line of argument isn't always completely bogus; . . .
POWELL:
This line of reasoning is ALWAYS bogus when used in deductive arguments. There are NO appeals to authority that are not deductively fallacious, unless the authority is infallible. Either the argument will be invalid or the argument will be valid with a false premise.
For example, the following argument is a valid deductive argument, since it follows the modus ponens form, but the first premise is likely to be untrue so the argument is likely to be unsound:
1. If Powell claims Lowder is wrong then Lowder is wrong.
2. Powell claims Lowder is wrong.
Therefore
3. Lowder is wrong.
What you should say is something more like "This line of argument isn't always completely bogus when used in an INDUCTIVE argument . . ."
Doing that, however, would require you to revamp much of your fallacy list including adding an important discussion concerning the relevance and value of inductive arguments.
Truth is worth that, don't you think? This might be especially worthwhile since other fallacy sites tend to be similarly in error.
> ATHEISM WEB:
>
> . . . for example, it may be relevant to refer to a
> widely-regarded authority in a particular field, if
> you're discussing that subject. For example, we can
> distinguish quite clearly between:
>
> "Hawking has concluded that black holes give off radiation"
> and
>
> "Penrose has concluded that it is impossible to build an
> intelligent computer"
POWELL:
It doesn't matter what Hawking or Penrose think about anything when trying to determine the validity of any deductive arguments they might propose. It matters when you use their expert opinion in an inductive argument to determine whether certain premises of a deductive or inductive argument are likely to be true.
> ATHEISM WEB:
>
> Hawking is a physicist, and so we can reasonably expect
> his opinions on black hole radiation to be informed.
POWELL:
When you say "we can reasonably expect" then you would seem to be speaking of inductive arguments, not the 100% certain - to - be - true - cannot - be - false deductive arguments, yet you say nothing of induction. Can you see how the reader might be misled?
> ATHEISM WEB:
>
> Penrose is a mathematician, so it is questionable
> whether he is well-qualified to speak on the subject
> of machine intelligence.
POWELL:
The virtue of the proponent of a deductive argument is IRRELEVANT to the validity of his argument. It doesn't matter if the proponent is the most notorious liar on the planet or the most respected logician, that should not change one iota the VALIDITY of any arguments they might propose.
Their virtue could affect the strength of any INDUCTIVE arguments they might propose.
I hope to hear your response.
John Powell
[Edited only to remove erroneous attribution of article to specific authors. -DM-]
I would like to bring to your attention what appears to me to be a mistake in your fallacy list in
The Atheism Web
Logic and Fallacies
> http://www.infidels.org/news/atheism/copyright.html
>
> ATHEISM WEB:
>
> The editors of these web documents have attempted to
> verify the accuracy and correctness of the information
> contained in them, as far as is metaphysically possible.
> Mistakes can and do happen, and so far it seems no
> omnipotent beings have intervened to correct them.
> If you use the information in these documents, you do
> so at your own risk.
POWELL:
Although I'm not an Omnibeing, I am hereby notifying you of what I think is a mistake.
> http://www.infidels.org/news/atheism/logic.html
>
> ATHEISM WEB:
>
> Many types of argument exist; we will discuss the
> deductive argument. Deductive arguments are generally
> viewed as the most precise and the most persuasive;
> they provide conclusive proof of their conclusion,
> and are either valid or invalid.
POWELL:
There is no mention anywhere on this page about inductive arguments per se, so the assumption of the reader is that you are discussing only deductive fallacies, not inductive fallacies.
> ATHEISM WEB:
>
> Argumentum ad verecundiam
> The Appeal to Authority uses admiration of a famous
> person to try and win support for an assertion.
> For example:
>
> "Isaac Newton was a genius and he believed in God."
>
> This line of argument isn't always completely bogus; . . .
POWELL:
This line of reasoning is ALWAYS bogus when used in deductive arguments. There are NO appeals to authority that are not deductively fallacious, unless the authority is infallible. Either the argument will be invalid or the argument will be valid with a false premise.
For example, the following argument is a valid deductive argument, since it follows the modus ponens form, but the first premise is likely to be untrue so the argument is likely to be unsound:
1. If Powell claims Lowder is wrong then Lowder is wrong.
2. Powell claims Lowder is wrong.
Therefore
3. Lowder is wrong.
What you should say is something more like "This line of argument isn't always completely bogus when used in an INDUCTIVE argument . . ."
Doing that, however, would require you to revamp much of your fallacy list including adding an important discussion concerning the relevance and value of inductive arguments.
Truth is worth that, don't you think? This might be especially worthwhile since other fallacy sites tend to be similarly in error.
> ATHEISM WEB:
>
> . . . for example, it may be relevant to refer to a
> widely-regarded authority in a particular field, if
> you're discussing that subject. For example, we can
> distinguish quite clearly between:
>
> "Hawking has concluded that black holes give off radiation"
> and
>
> "Penrose has concluded that it is impossible to build an
> intelligent computer"
POWELL:
It doesn't matter what Hawking or Penrose think about anything when trying to determine the validity of any deductive arguments they might propose. It matters when you use their expert opinion in an inductive argument to determine whether certain premises of a deductive or inductive argument are likely to be true.
> ATHEISM WEB:
>
> Hawking is a physicist, and so we can reasonably expect
> his opinions on black hole radiation to be informed.
POWELL:
When you say "we can reasonably expect" then you would seem to be speaking of inductive arguments, not the 100% certain - to - be - true - cannot - be - false deductive arguments, yet you say nothing of induction. Can you see how the reader might be misled?
> ATHEISM WEB:
>
> Penrose is a mathematician, so it is questionable
> whether he is well-qualified to speak on the subject
> of machine intelligence.
POWELL:
The virtue of the proponent of a deductive argument is IRRELEVANT to the validity of his argument. It doesn't matter if the proponent is the most notorious liar on the planet or the most respected logician, that should not change one iota the VALIDITY of any arguments they might propose.
Their virtue could affect the strength of any INDUCTIVE arguments they might propose.
I hope to hear your response.
John Powell
[Edited only to remove erroneous attribution of article to specific authors. -DM-]