Noonan's Third Premise

Noonan's Third Premise

Let us restate Noonan's third premise:

Premise (3)

 

 

 

 

A human conceptus is a human being.

This is the premise which absorbs most of Noonan's efforts in his article. Noonan argues that a human conceptus is a human by 1) putting forward arguments that every human conceptus is a human being and 2) criticizing arguments which conclude that not every human conceptus is a human being. Let us take Noonan's criticisms first.

Noonan's Criticisms of Arguments against Premise 3:

The Viability Argument:

 

 

 

 

 

 

A human conceptus is viable when it can live apart from the mother.

 

 

 

 

 

 

1

A human conceptus is a human being when it is viable.

 

 

2

Not every human conceptus is viable.

 

Therefore

3

Not every human conceptus is a human being.

1&2

 

 

 

 

Criticism 1:

The time of viability is affected by technology and, possibly, race.

 

Criticism 2:

The weight and length of a fetus are better indicators of viability than age.

 

Cricitism 3:

Infants are completely dependent on care-givers.

 

Given the variability of viability, it is capricious to treat viability as a necessary condition on being a human being. Hence the Viability Argument is clearly unsound, since premise (1) is false.

The Experience Argument:

 

 

 

 

 

 

Experience, memories, and perceptions are required to be considered a human being.

 

 

 

 

 

 

1

Every human being has experiences.

 

 

2

Not every human conceptus has experiences.

 

Therefore

3

Not every human conceptus is a human being.

1&2

 

 

 

 

Criticism 1:

The human conceptus reacts to stimuli at 8 weeks "and at least at that point is experiencing."

 

Criticism 2:

Comatose or catatonic adults are presumably human beings.

 

Criticism 3:

Infants can be said to have little experience.

 

Criticism 4:

There is no reason to think that experience should count for humanity.

 

Noonan's criticisms are persuasive on two scores: they show that premise (1) is not true, and they show that premise (2) is not true. We conclude that The Experience Argument is unsound.

The Social Visibility Argument:

 

 

 

 

 

 

The human conceptus is not able to communicate and is not a member of society.

 

 

 

 

 

 

1

Every human being is socially visible.

 

 

2

Not every human conceptus is socially visible.

 

Therefore

3

Not every human conceptus is a human being.

1&2

 

 

 

 

Criticism 1:

So if we cut off a person or group of people from society at large, they're no longer human beings?

 

Criticism 2:

Any division of human being from non-human being in terms of social visibility would open the door to great injustice.

 

Noonan's criticisms here are directed at premise (1). The second criticism is especially interesting, because what it argues is that in cases where premise (1) is assumed to be true, great wrongs are often perpetrated. But the deciding criticism is the first one. To see why, consider the case of Robinson Crusoe. One can be utterly absent from society and nonetheless be a human being. We conclude that the Social Visibility Argument is unsound.

Since Noonan finds each of the three arguments against premise (3) of his argument to be unsound, he correctly concludes that we have no reason to think that premise (3) of his argument is false. But we cannot conclude that premise (3) of Noonan's Argument is true, since having no reason to think the premise is false is no reason to think it is true. For all we know, it could still be false. Noonan must, then, give sound arguments to show that premise (3) of his argument is true.

Noonan's arguments for Premise (3):

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.

1&2

 

The Argument from Conception:

 

 

 

 

 

 

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.

1&2

 

The Argument from Genetic Code:

 

 

 

 

 

 

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.

1&2

Unfortunately for Noonan, each of these arguments is also unsound. Can you see why?