Is "tu quoque" really a logical fallacy?

by George J. Dance

"Tu quoque" is a Latin term that translates as "you too." It is the name of a line of argument that is considered a logical fallacy. Here is a standard explanation, from Wikipedia:

Tu quoque ... or the appeal to hypocrisy, is a fallacy that intends to discredit the opponent's argument by asserting the opponent's failure to act consistently in accordance with its conclusion(s)... An example would be:

Peter: "Bill is guilty of defrauding the government out of tax dollars."
Bill: "How can you say that when you yourself have 20 outstanding parking tickets?"
https://en.wikipedia.org/wiki/Tu_quoque

Wikipedia adds that tu quoque "is a fallacy because the moral character or actions of the opponent are generally irrelevant to the logic of the argument." It also calls it a "red herring"(a diversion) and an "ad hominem" (an attack not on the argument but on the person making the argument), but those two objections to it reduce to the first one: a statement can be a red herring or an ad hominem only if it is irrelevant to an argument.

So, then, a tu quoque is a fallacy only if it is irrelevant to an argument. A moral argument, though, is an argument about right and wrong (about what people ought to do and not do); and a person's actions (what he does and does not do) reflect his moral beliefs (what he believes people ought to do and not do). So: a tu quoque is not a fallacy in a moral argument.

Consider the above example. Peter's parking tickets are indeed irrelevant to whether Bill is withholding money from the government; but it is not irrelevant to whether Bill is doing something wrong. Peter is not just giving us the information that Bill is withholding money from the government. By his use of the terms "guilty" and "defrauding," he is relying on (or smuggling in) tacit moral premises to imply a few equally tacit conclusions:

1. It is morally wrong to commit fraud.
2. Withholding money from the government is fraud.
3. Bill is withholding money from the government.
4. Therefore, Bill is guilty of fraud.
5. Therefore, Bill should stop withholding money from the government; and
6. Therefore, the rest of us should think badly of Bill for withholding that money.

That is the argument that Bill is addressing. He is in fact challenging Peter's premises, with a similarly tacit argument.

1. By not paying his parking tickets, Peter is also withholding money from the government.
2. Therefore, if Peter believed his third premise were true, he would pay his parking tickets (by his first premise).
3. Therefore, Peter does not believe one of either his first or fourth premises. Peter's argument contains a false premise, by his own expressed belief.
4. Therefore, Peter's argument, by his own expressed belief, is invalid.

That puts the onus back on Peter. Moral rules are "universalizable," which is just a fancy term meaning that they are rules not about what Bill should do or not do, but about what people (ie, everyone) should do or not do. The principle of universalizability states that the moral rules that apply to one person apply to every other person, except where there is a good moral reason for treating them differently; equal treatment is the default.

In order to save his argument, Peter has to justify such a difference in treatment. He can argue either that not paying parking tickets is different from not paying taxes, or that different rules should apply to Peter from those that apply to Bill. On the other hand, by simply claiming a fallacy on Bill's part, Peter has to do nothing at all: he wins his point without having to make it; Bill loses to a bad argument, that Peter did not prove (or even properly make).

To repeat: tu quoque is not a fallacy in a moral argument; falsely labelling it as such is itself fallacios.

How a reductio ad absurdum does not work

by George J. Dance

Ever heard of Grab World? Matt Bruenig, an attorney who used to troll libertarians on progressive website Demos until he was fired for Twitter trolling, once used the idea of Grab World (a thought experiment invented by libertarian philosopher Roderick Long) to allegedly show how ridiculous the non-aggression principle is. When challenged by some libertarians, who in his words "couldn't handle this," Bruenig wrote a follow-up column on his own blog  "as a learning opportunity to help people understand how the reductio ad absurdum works."

He began by explaining that "A reductio is a type of argument in which you accept a premise and use it to generate a conclusion that strikes people as absurd," and then gave the argument form:

1. If X, then Y.
2. Y is totally absurd.
3. Therefore X is not true.

Next he fleshed out the form with his Grab World example: "the premise was justice requires that we follow the non-aggression principle and the conclusion was people can come into the house you live in and grab up the stuff and you cannot use force to prevent that. So we plug it in.

1. If justice requires that we follow the non-aggression principle, then people can come into the house you live in and grab up the stuff and you cannot use force to prevent that.
2. It is totally absurd to say that 'people can come into the house you live in and grab up the stuff and you cannot use force to prevent that.'
3. Therefore it is not true that justice requires that we follow the non-aggression principle."

Almost every part of Bruenig's explanation is wrong. First, that is not "how the reductio ad absurdum works". His argument form is not even a reductio ad absurdum (RAA). An RAA, or indirect proof, works by positing an assumption (or supposition), and then proving it false by showing logically that it leads to a contradiction.

Second, Bruenig is confused about what premises and conclusions are. The premises in his argument are steps 1 and 2, and the conclusion is step 3. What he calls "the premise" and "the conclusion" are actually called the antecedent and consequent of a conditional. Third, what he calls "the premise" does not "generate" what he calls "the conclusion" - he merely asserts both together, as two halves of one unproven premise (step 1). 

Fourth, the above is not even a valid argument form (although it looks like one: modus tollens, or denying the consequent). It does not logically follow, from "If X, then Y" and "Y is totally absurd," that "X is not true" - all that would follow is "X is totally absurd," whatever Bruenig means by that. (He does not mean what logicians mean by "absurd," being contradictory or logically impossible.) 

Fifth, even if Bruenig's argument were valid, it would not be sound. A sound argument is a valid one with all true premises, which proves that its conclusion is true. There is no reason to think that either of Bruenig's premises is true. Almost every libertarian would deny the truth of his premise 1. Premise 2 looks a bit more plausible, but there is no reason to think it is true, either. (What if the "people [coming] into the house you live in" were bailiffs - or police seizing stolen goods - or even movers?)

In conclusion, let me show how an RAA argument really works:

1. Someone who knows logic would know what a valid argument is, and what the terms premise, conclusion, and reductio ad absurdum mean. (premise; see any logic text)
2. Assume Matt Bruenig is someone who knows logic. (assumption; beginning of RAA)
3. Then Matt Bruenig knows what a valid argument is, and what the terms premise, conclusion, and reductio ad absurdum mean. (1,2 hypothetical syllogism)
4. But Matt Bruenig does not know any of that. (premise; see above)
5. Therefore, Matt Bruenig is not someone who knows logic, (2-4 RAA)

I hope that readers find that argument instructive.

All that Bruenig's argument proves, on the other hand, is that he can pontificate on subjects about which he knows little or nothing: something that readers might find useful to keep in mind when reading his criticisms of libertarianism. 

An argument for self-ownership

by George J. Dance

Last week I posted a column about three rather silly arguments against the concept of self-ownership that I had found on the interwebs. After writing that, I went on to write the best argument I could for the concept; which I didn't print because of length. Here is that argument; criticisms welcome.

An argument for self-ownership

My own conclusion from reading Aaron's arguments is that some people could profit from learning more about both self-ownership and logic. The best way I can see of doing both is to present an argument for self-ownership in logical form:

1. To own something is to have a just claim to control the use of that thing. (definition)
2. Either people are owned, or they are not owned. (Av~A)
3. If people are owned, they are either owned by themselves, or by other people. (Av~A)
4. For one person to claim ownership of another person is slavery. (definition)
5. Slavery is unjust. (premise)
6. Therefore, people cannot be not owned by other people. (1,4,5)
7. Therefore, either people own themselves, or they are not owned. (2,3,6)
8. Assume people are unowned. (Assumption)
9. Either it is wrong for people to use things no one owns, or it is not wrong. (Av~A)
10. Then either it is wrong for adults to use other adults' unowned bodies, or it is not wrong. (8,9)
11. Assume that it is not wrong for adults to use other adults' bodies. (Assumption)
12. Then it is not wrong for a man to use a woman's body for sex.
13. Then it is not wrong for a man to use a woman's body for sex, if the woman does not agree.
14. But it is wrong for a man to use a woman's body for sex, if the woman does not agree. (premise)
15. Then, if people's bodies are unowned, it must be wrong for adults to use other adults' bodies. (11-14; Assumption discharged)
16. Now assume that it is wrong for adults to use other adults' bodies. (Assumption)
17. Then it is wrong for a man to use a woman's body for sex.
18. Then it is wrong for a man to use a woman's body for sex, even if the woman agrees.
19. But it is not wrong for a man to use a woman's body for sex, if the woman agrees. (premise)
20. Then, if people's bodies are unowned, it must not be wrong for adults to use other adult's bodies. (16-19; Assumption discharged)
21. Then, if people's bodies are unowned, it must be both wrong and not wrong to use other adults' bodies for sex. (15,20)
22. Therefore, people are not unowned. (8-21; Assumption discharged)
23. Therefore, people own themselves. (7,22)

The validity of any step can be challenged. So can the truth of any of the 3 explicit premises: that slavery is unjust, that it is wrong for a man to use a woman's body for sex if the woman does not agree, and that it is not wrong for a man to use a woman's body for sex if the woman does agree.

We could stop right there - the above argument is complete as is - but it may be useful to see what the conclusion implies; so let me add a few more steps, purely for the sake of illustration:

24. It is wrong to use an owned resource if the owner does not agree. (1)
25. It is not wrong to use an owned resource if the owner does agree. (1)
26. It is wrong for a man to use a woman's body for sex, if the woman does not agree. (23,24)
27. It is not wrong for a man to use a woman's body for sex, if the woman does agree. (23,25)

The fact that these conclusions (#26 and #27) are the same as the earlier premises (#14 and #19) is not circular, since those conclusions are not deduced from those premises. My only reason for including these steps was to show that #26 and #27 did not contradict #14 and #19; if they did, then the conclusion that people are self-owners would be absurd, too. An argument by reductio ad absurdum  could prove a conclusion by showing that the other alternatives are absurd, but in practice that would be of little use if that conclusion were equally absurd.

Silly arguments against self-ownership

by George J. Dance:

May 10, 2017 - Libertarians often talk about "self-ownership." What is it? To quote an encyclopedia definition: "Self-ownership (or sovereignty of the individual, individual sovereignty or individual autonomy) is the concept of property in one's own person, expressed as the moral or natural right of a person to have bodily integrity, and be the exclusive controller of her or his own body and life."

I am no fan of the term. "Ownership" over one's own body and life is different, in crucial ways, from "ownership" of external things, like a car, and using the same term for both blurs those differences. One has to act to acquire a car; while one has "self-ownership" simply by existing. One can sell a car to another person, meaning that the other person now owns it; but I cannot imagine how anyone could rightfully come to own another person. Finally, ownership, and possession and control, of oneself are indistinguishable – some libertarians even ground self-ownership on the metaphysical fact that people do possess and control their own bodies – while it is perfectly sensible to imagine a car being owned by one person, but possessed and controlled by someone else.

So I would prefer to use a different term, like the ones the encyclopedia offers: individual sovereignty or individual autonomy. However, I have no trouble with the concept as properly understood. Anti-propertarians, on the other hand, do seem to have trouble with the concept; perhaps because of the problems with the term noted above. In any case, on the web one often encounters people arguing against the very idea of self-ownership.

One popular argument that I often run into is "Three Refutations of Self-Ownership," published on an anarchist discussion forum years ago. It consists of three arguments meant to show that self-ownership is  (i) an oxymoron, (ii) immoral and unjust, and (iii) metaphysically impossible; posted with the invitation to "Please critique freely". Being a sucker for logical arguments, I had to respond to the invitation.

A Refutation of Self-Ownership #1 (With No Consideration of Cartesian Dualism)

1. Ownership requires a thing A that owns and a thing B that is owned.
2. Self-ownership requires that one A owns one’s body B.
3. If A and B were the same – i.e. if one and one’s body were one and the same thing – then A and B would both own and be owned.
4. Ownership implies an ability to control, direct, dominate, dispose of, defend, manage, and rent a thing.
5. If A and B were the same, then A would be controlling B, and B would be controlling A, and so forth, ad absurdum, so that true ownership would not really exist.
6. Therefore, if A and B are the same, then self-ownership is an oxymoron.

The false premise here is 5. If A and B were two different people, then it would be absurd for A to control B and for B to control A at the same time (precisely what makes the democratic idea of the citizens controlling a government that controls them absurd). What would happen if A and B disagreed? A would have to give in to B, and B would have to give in to A; in what sense, then, would either of them be in control?

However, the assumption is that A and B are the same person. So let us make that identity clear, by using just the one symbol, and rewriting premise 5 as:
5. If A and A were the same thing, then A would be controlling A, and A would be controlling A, and so forth, ad absurdum, so that true ownership would not really exist.
No absurdity there. Since premise 5 is false, the argument is unsound.

A Refutation of Self-Ownership #2 (With Consideration of Cartesian Dualism)

1. Ownership requires a thing A that owns and a thing B that is owned.
2. Self-ownership requires that one A owns one’s body B.
3. If A and B were not the same – i.e. if one’s mind/will and one’s body were not one and the same thing – then A would be a mind/will and B would be a living human body.
4. It is immoral and unjust to claim ownership of a living human body.
5. Therefore, self-ownership is immoral and unjust.

Premise 4 looks like the false one here. It might indeed always be "immoral or unjust to claim ownership of a living human body;" but why think it is? Perhaps the author was thinking about slavery, and reasoning implicity:
4a) Claiming ownership of a living human body is slavery.
4b) Slavery is immoral and unjust.
4c) Therefore, claiming ownership of a living human body is immoral and unjust.
But the definition of slavery in 4a) is misstated. Slavery is claimed ownership of someone else's living body. So all that this argument, if sound, would prove is that claiming ownership of someone else's living body is immoral and unjust; and of course claiming self-ownership is not claiming that. Since premise 4 is false, the argument is again unsound.

A Refutation of Self-Ownership #3 (With Consideration of Cartesian Dualism)

1. Ownership requires a thing A that owns and a thing B that is owned.
2. Self-ownership requires that one A owns one’s body B.
3. If A and B were not the same – i.e. if one’s mind/will and one’s body were not one and the same thing – then A would be a mind/will and B would be a living human body.
4. If the mind exists outside of the living human body – i.e. if the mind is a separate, non-physical entity – then the mind is intangible, whereas the human body is tangible.
5. It is not possible for a thing without physical tangibility to act upon a thing with physical
tangibility.
6. Therefore, self-ownership is metaphysically impossible.

In this case, the premises are all true, but the conclusion is a non-sequitur. Premise 4 contains
an assumption – "If the mind exists outside of the living body" etc. – that is not discharged in the conclusion. So to be valid the conclusion would have to be stated as:
6'. "Therefore, if the mind exists outside of the living body – i.e. if the mind is a separate, non-physical entity – then self-ownership is metaphysically impossible."
 –  Which would refute any libertarians who do argue that their minds are non-physical things that exist outside their bodies. But what libertarians do that? Since the conclusion does not follow from the premises, the argument is invalid.

Also read: An argument for self-ownership