Recall that knowing that an argument is unsound tells us nothing, repeat nothing, about the truth or falsity of the conclusion. Showing an argument unsound is equivalent to discarding the argument; we throw the argument out since it doesn't give us any reason for thinking that the conclusion is true, any more than it gives us a reason for thinking that the conclusion is false.

So Noonan has to provide additional arguments to show that

• Every human conceptus is a human being.

Unfortunately it is a relatively trivial matter--much to the dismay of Noonan, I'm sure--to show that each of these arguments is likewise unsound. The arguments are valid, so you should be able to state, in each case, which premise is false and why it is false.

In particular, the Argument from Potentiality,

1. If a human conceptus is potentially a human being, then it is a human being.

2. A human conceptus is potentially a human being.

Therefore

3. A human conceptus is a human being.

assumes with premise (1) that anything which is potentially an F is an F, where F is some property. But clearly this general principle is false, since, for example, a pre-med student is potentially a physician but no one would make the mistake of thinking that the pre-med student is a physician. Potentially being something, a doctor or lawyer or what have you, does not make you that thing. But then there's no reason to think that a human conceptus is a human being just because it is potentially a human being. Hence premise (1) is presumably false, since Noonan gives us no reason for thinking that being a human being is a special property such that, if one is potentially a human being, one is a human being.

Similarly, premise (1) of the Argument from Conception is false.

1. If a human conceptus is conceived by human parents, then it is a human being.

2. A human conceptus is conceived by human parents.

Therefore

3. A human conceptus is a human being.

It is certainly possible for human parents to conceive something which is clearly not a human being. The history of severe and tragic deformation--i.e., anencephalic and headless fetuses, etc--provides numerous examples.

Finally, premise (1) of the Argument from Genetic Code is also clearly false.

1. If x has a human genetic code, then x is a human being.

2. A human conceptus has a human genetic code.

Therefore

3. A human conceptus is a human being.

For if the only condition sufficient for being a human being is having human genetic code, then each cell in my body is a human being, and every time I bruise myself I am a mass murderer. But that is patently absurd, so premise (1) cannot be true.

We seem to be at an impasse. We find that arguments for the thesis that the human conceptus is a human being are unsound, and we find that arguments for the thesis that not every human conceptus is a human being are unsound.

What have learned from Noonan? Very little, it turns out. We simply don't know whether the human conceptus is a human being. We're completely in the dark on the status of the human conceptus.

I submit that we are at this impasse for a very good reason. We aren't getting anywhere in establishing whether or not the fetus is a person because we are asking the wrong question.

Thomson sets aside the question of whether or not a human conceptus is a human being by simply assuming that, indeed, the human conceptus is a human being or, as she puts it, a fetus is a person. Debates over abortion are ordinarily thought to hinge on the status of the fetus. If it's a person, then it is usually thought that the argument against abortion is sound, much as we saw with Noonan. The step from "a fetus is a person" to "abortion is morally wrong" is usually taken for granted.

As Thomson points out, that the step to showing that abortion is morally wrong from the assumption that a fetus is a person is by no means obvious or straightforward. Thomson shows this by appeal to the Principle of Analogy in the Case of the Famous Unconscious Violinist. If Thomson is correct, it is morally permissible for you to unhook yourself from the Violinist and thereby let the Violinist die. But if that's the case, then there is something wrong with the argument which concludes that it is morally wrong for a woman to abort a pregnancy due to rape. In particular, since it has a false conclusion and is valid, it must have a false premise.

In fact, it is precisely the point of Thomson's argument to show that the abortion (Noonan's) argument is unsound because one of its premises is false. It is false that the fetus' right to life outweighs the mother's right to determine what happens in and to her body. But is it generally false, or is it only false in cases of pregnancy due to rape? Surely there are a number of variations on the basic abortion argument. That is to say, by granting for the sake of argument that the fetus is a person Thomson correctly teaches us that it does not thereby follow that abortion is morally wrong. But the task of showing that the proposition,

• If the fetus is a person then abortion is morally impermissible,

is false requires an astonishingly intricate and complicated argument.

As a discussion of Thomson, let us briefly consider each step in turn.

Thomson opens by explaining that it is no straightforward matter to get from the premise that the fetus is a person to the moral impermissibility of abortion. What is required is an additional assumption like

• P1: A fetus' right to life is more stringent than a mother's right to determine what happens in and to her body.

But this assumption is clearly false. To show that it is false, Thomson constructs the Case of the Famous Unconscious Violinist. Using the Principle of Analogy, Thomson is able to show that if we think intuitively, as most do, that it would be perfectly morally permissible for one to disconnect oneself from the Famous Unconscious Violinist, then we should think that it is morally permissible for a woman pregnant due to rape to get an abortion. But then the conclusion to Thomson's variation on Noonan's argument is false, which implies that the above assumption must be false since the argument is valid and every other premise is either true or granted for the sake of argument. This, note, is a style of argument that Thomson will employ repeatedly.

Thomson's Variation on Noonan

3/13/02

Thomson's Argument

Kidnapping is morally wrong.

Rape is morally wrong.

The hospital stay would last nine months.

The pregnancy would last nine months.

The violinist is an innocent human being.

The fetus is an innocent human being.

Disconnecting from the violinist amounts to killing the violinist.

Aborting the pregnancy amounts to killing the fetus.

The famous violinist is famous and can play the violin.

The fetus is neither famous nor can it play the violin.

You may not be female.

The woman is female.

You cannot leave the hospital and so do not have freedom of movement.

The woman has, for the most part, freedom of movement.

Disconnecting from the violinist is merely refusing to save.

Aborting the pregnancy is actively killing the fetus.