John Powell
September 20th 2003, 04:41 PM
NIZKOR: Ad Hominem Tu Quoque
POWELL:
Since NIZKOR may be the best source of fallacies on the web, I'll focus on criticizing them. Let's consider the fallacy of Ad Hominem Tu Quoque.
http://www.nizkor.org/features/fallacies/ad-hominem-tu-quoque.html
NIZKOR:
Fallacy: Ad Hominem Tu Quoque
-----------------------------
Also Known as: "You Too Fallacy"
Description of Ad Hominem Tu Quoque
This fallacy is committed when it is concluded that a person's claim is false because 1) it is inconsistent with something else a person has said or 2) what a person says is inconsistent with her actions. This type of "argument" has the following form:
Person A makes claim X.
Person B asserts that A's actions or past claims are inconsistent with the truth of claim X.
Therefore X is false.
The fact that a person makes inconsistent claims does not make any particular claim he makes false (although of any pair of inconsistent claims only one can be true - but both can be false). Also, the fact that a person's claims are not consistent with his actions might indicate that the person is a hypocrite but this does not prove his claims are false.
POWELL:
The text above applies to the deductive form of the fallacy. It ignores the inductive form.
NIZKOR:
Examples of Ad Hominem Tu Quoque
Bill: "Smoking is very unhealthy and leads to all sorts of problems. So take my advice and never start."
Jill: "Well, I certainly don't want to get cancer."
Bill: "I'm going to get a smoke. Want to join me Dave?"
Jill: "Well, I guess smoking can't be that bad. After all, Bill smokes."
POWELL:
This is a deductive fallacy because the fact that Bill smokes does not necessarily mean that smoking is good (or bad). However, this is not necessarily an inductive fallacy since what people do is generally a better indicator of what is acceptable than what they say to do. Given enough smokers, the inductive argument would be strong.
NIZKOR:
Jill: "I think the gun control bill shouldn't be supported because it won't be effective and will waste money."
Bill: "Well, just last month you supported the bill. So I guess you're wrong now."
POWELL:
This is a deductive fallacy because the fact that a person had a different belief in the past does not necessarily mean the new belief is false (or true). This also appears to be an inductive fallacy (perhaps unintentionally) because people who change their opinion usually do so because there is better evidence for the new position. However, the argument would not be inductively fallacious if there were enough critics of Jill's new view.
Furthermore, the argument would not necessarily be inductively fallacious if the conclusion were reversed to say ". . . you were wrong before" which NIZKOR easily might have done.
NIZKOR:
Peter: "Based on the arguments I have presented, it is evident that it is morally wrong to use animals for food or clothing."
Bill: "But you are wearing a leather jacket and you have a roast beef sandwich in your hand! How can you say that using animals for food and clothing is wrong!"
POWELL:
This is a deductive fallacy because the fact that someone's actions are inconsistent with their claimed beliefs does not necessarily mean those beliefs are true (or false). However, this is not an inductive fallacy because a person's behavior is generally a better indicator of what they believe is acceptable to do than what they claim to believe is acceptable to do.
NIZKOR did not give an example of what is perhaps the most common example of this deductive fallacy, specifically that of replying to someone's criticism by pointing out that the critic does essentially the same thing. Such an argument would be deductively fallacious, but not necessarily inductively fallacious.
Summary.
NIZKOR did not clarify here which examples were deductive and which were inductive versions (or both) of the fallacy. They seemed to be completely ignoring the inductive form. All three examples are deductive fallacies. However, only one of them is also an inductive fallacy (perhaps by accident). The last one isn't an inductive fallacy and the other one is not necessarily an inductive fallacy.
If someone were trying to determine whether their inductive arguments committed the fallacy of Ad Hominem Tu Quoque they could easily be misled by what NIZKOR wrote.
John Powell
POWELL:
Since NIZKOR may be the best source of fallacies on the web, I'll focus on criticizing them. Let's consider the fallacy of Ad Hominem Tu Quoque.
http://www.nizkor.org/features/fallacies/ad-hominem-tu-quoque.html
NIZKOR:
Fallacy: Ad Hominem Tu Quoque
-----------------------------
Also Known as: "You Too Fallacy"
Description of Ad Hominem Tu Quoque
This fallacy is committed when it is concluded that a person's claim is false because 1) it is inconsistent with something else a person has said or 2) what a person says is inconsistent with her actions. This type of "argument" has the following form:
Person A makes claim X.
Person B asserts that A's actions or past claims are inconsistent with the truth of claim X.
Therefore X is false.
The fact that a person makes inconsistent claims does not make any particular claim he makes false (although of any pair of inconsistent claims only one can be true - but both can be false). Also, the fact that a person's claims are not consistent with his actions might indicate that the person is a hypocrite but this does not prove his claims are false.
POWELL:
The text above applies to the deductive form of the fallacy. It ignores the inductive form.
NIZKOR:
Examples of Ad Hominem Tu Quoque
Bill: "Smoking is very unhealthy and leads to all sorts of problems. So take my advice and never start."
Jill: "Well, I certainly don't want to get cancer."
Bill: "I'm going to get a smoke. Want to join me Dave?"
Jill: "Well, I guess smoking can't be that bad. After all, Bill smokes."
POWELL:
This is a deductive fallacy because the fact that Bill smokes does not necessarily mean that smoking is good (or bad). However, this is not necessarily an inductive fallacy since what people do is generally a better indicator of what is acceptable than what they say to do. Given enough smokers, the inductive argument would be strong.
NIZKOR:
Jill: "I think the gun control bill shouldn't be supported because it won't be effective and will waste money."
Bill: "Well, just last month you supported the bill. So I guess you're wrong now."
POWELL:
This is a deductive fallacy because the fact that a person had a different belief in the past does not necessarily mean the new belief is false (or true). This also appears to be an inductive fallacy (perhaps unintentionally) because people who change their opinion usually do so because there is better evidence for the new position. However, the argument would not be inductively fallacious if there were enough critics of Jill's new view.
Furthermore, the argument would not necessarily be inductively fallacious if the conclusion were reversed to say ". . . you were wrong before" which NIZKOR easily might have done.
NIZKOR:
Peter: "Based on the arguments I have presented, it is evident that it is morally wrong to use animals for food or clothing."
Bill: "But you are wearing a leather jacket and you have a roast beef sandwich in your hand! How can you say that using animals for food and clothing is wrong!"
POWELL:
This is a deductive fallacy because the fact that someone's actions are inconsistent with their claimed beliefs does not necessarily mean those beliefs are true (or false). However, this is not an inductive fallacy because a person's behavior is generally a better indicator of what they believe is acceptable to do than what they claim to believe is acceptable to do.
NIZKOR did not give an example of what is perhaps the most common example of this deductive fallacy, specifically that of replying to someone's criticism by pointing out that the critic does essentially the same thing. Such an argument would be deductively fallacious, but not necessarily inductively fallacious.
Summary.
NIZKOR did not clarify here which examples were deductive and which were inductive versions (or both) of the fallacy. They seemed to be completely ignoring the inductive form. All three examples are deductive fallacies. However, only one of them is also an inductive fallacy (perhaps by accident). The last one isn't an inductive fallacy and the other one is not necessarily an inductive fallacy.
If someone were trying to determine whether their inductive arguments committed the fallacy of Ad Hominem Tu Quoque they could easily be misled by what NIZKOR wrote.
John Powell