1. The arguer tries to point out that the ACLU is being inconsistent. Its position on the legal status of the fetus in the Harris case is inconsistent with its position on abortion.

The argument:

(1) The ACLU argues that Harris should not be executed because his brain was damaged by his mother’s drinking when he was a person in his mother’s womb.

But the ACLU said in Roe v. Wade that the fetus is not a human life (person) at all.

¯ The ACLU is inconsistent.

¯ The ACLU’s argument against Harris’ execution is flawed. (Implied)

The conclusion simply does not follow. The ACLU’s position on abortion is actually irrelevant for the arguments presented here. The question is, Is their current argument good? not “are they consistent with what they said elsewhere.” (Sometimes inconsistency is relevant--when it’s in the same argument. Assuming that there is an inconsistency here, the arguer would be correct only if he were to conclude that the ACLU is being inconsistent. The conclusion that they are wrong about the Harris case simply does not follow. So, this argument:

(2) The ACLU is inconsistent (between the Harris case and Roe v. Wade).

¯ The ACLU’s argument against Harris’ execution is flawed.

Simply is invalid. The conclusion of 2 does not follow from the premise. Indeed, the ACLU might be inconsistent, but it does not mean that they are wrong in the Harris case. But do they have to be inconsistent? Can one hold these two things? Yes, one does not have to hold that the fetus is a person to say that mistreating it can result in bad behavior later in life. Perfectly consistent.

2. The American Indian population is larger today than in Columbus’s time.

¯ The Indian population did not suffer genocide.

This is non sequitur. If the Jewish population in Europe reaches its pre-WWII population (which is likely), will that mean there was no genocide? The question isn’t, how many are there now, but how many would there be but for. The American Indian population was reduced from about a million to less than 30,000.

3. This argument makes an analogy. It tries to show that it is a “lie” that condoms really protect. The heart of the argument depends on the analogy between the airplane and having sex. Let’s look at it:

(1) Condom failure rate can be as high as 20 percent.

Using a condom with a 20 percent failure rate is like flying with a 20 percent chance of a fatal plane crash (both risk death).

No responsible person would fly with a 20 percent chance of fatally crashing. (Unexpressed Premise)

¯ No responsible person would use condoms to prevent AIDS (implied).

¯ The claim that condoms protect against AIDS is a lie.

Problems: First, are condom failures really “as high as” 20%? Not really. But, grant that they do fail. Look at the analogy. Does is work? In a fatal plane crash, you die. If you condom fails, do you die? The probability of getting AIDS from a failed condom is the result of the product of a) the chance that the condom failed multiplied by b) the chance that your partner is infected with the AIDS virus; multiplied by c) the chance that you will get the virus by having unprotected sex with an infected person.

a) 20% failure rate

b) 10% is infected (that’s too high, but let’s be generous).

c) 1 in 100 chance of getting it (that’s actually high, also.)

1/5 x 1/10 x 1/100 = 1/5000 or .02%. This is one thousand times smaller than the 20% figure from the plane crash. So, on average, you would have to have unprotected sex 1000 times to get AIDS. With a condom, it goes to 5000. When used correctly, condoms are much more effective than this, though.

4. Ehrlich says that an American baby has a much greater environmental impact than those of other countries.

¯ Ehrlich and his liberal supporters are against family values.

A total non sequitur. The conclusion simply doesn’t follow from the premises.