Sharon asked:

I can't remember the name or specifics of this particular philosophical dilemma. It involves the
metamorphosis of one thing into another thing. The dilemma is that it is not clear when "the thing"
stops being the first thing and starts becoming — or is? — the second.

This question arises out of a discussion on abortion and the question, "When does something
become human?" — the difficulty in answering this question seems to lead to a difficulty in defining
what a human being IS. Although as I write this, I wonder if a [late] Wittgensteinian approach to
definition — family resemblances — might be helpful in defining what a human is. Please illumine me.
I would like to know the specifics of the dilemma but also any thoughts on the issue pertaining to
abortion.

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The problem you have described is a variant on an ancient paradox concerning the use of terms
whose meaning is intrinsically vague. The version of the paradox that I like is called the Drinking
Problem.

I estimate that I drink no more than twenty units of alcohol every week, the equivalent of ten pints of
beer. Let us assume that my estimate is in fact correct. My drinking, you will be pleased to hear, is
within the UK government health guidelines. According to those guidelines — and according to
common sense — I do not have a drink problem.

Now suppose that, unknown to me, my average consumption increases by one tenth of one unit. If I
didn't have a drinking problem before, then an extra tenth of a unit per week cannot amount to a
drinking problem. In general, it seemslogical to say that whatever the number of units of alcohol you
consume in a week, if that number is not sufficient to constitute a drinking problem, then an extra
tenth of a unit isn't going to turn it into one.

It doesn't take too much intelligence to work out that it follows strictlyfrom the statement I have just
made that even if I drink twenty pints of beer a day, I don't have a drinking problem! You just start with
the statement, 'One unit of alcohol a week is not a drinking problem' and keep adding on tenths of a
unit.

Biological metamorphosis is not really an example of the problem of vagueness. When a caterpillar
undergoes metamorphosis into a butterfly, it is not the case that the organism becomes less and less
a caterpillar and more and more a butterfly. Rather, the caterpillar goes through an intermediate
stage, after it has spun its cocoon, where its body is dissolved into a 'soup' of chemicals which then
form the body of the butterfly. No such intermediate stage exists in the gradual growth and maturation
of a human foetus.

Which brings us to the crucial question of abortion. A foetus does not 'metamorphose' into a human
being. It is human from the beginning. The question is whether there is any point in the development
of a foetus before which abortion would be justified and after which abortion would not be justified.
Here, one is tempted into the following argument. If you allow abortion at eight weeks, then in the
absence of any precise, identifiable difference between a foetus that is eight weeks old, and a foetus
that is eight weeks and one day, you are on a slippery slopetowards allowing abortion at nine weeks,
ten weeks, eleven weeks and so on.

This makes as much sense as the argument from Prohibitionists in the 20's that any amount of
alcohol consumption, however small, is on the 'slippery slope' towards alcoholism.

So what are we to say? Vague predicates do not respect the strict laws of logic. This is only a
problem if you think that terms which do not respect the laws of logic cannot have any sense, a view
which Wittgenstein argued powerfully against in his later philosophy, for example, in his discussion of
the complex 'family resemblances' that hold between different instances of a term (though this strictly
does not concern the question of vagueness).

We are still faced with the practical question of when, if ever, abortion is permissible, or when
enjoyment of alcohol does, or does not, constitute a drinking problem. The thing to realize is that
these are not special cases, we make judgements based on vague differences all the time. It is only
when we are faced with an important moralquestion, like the question of abortion, that we feel
suddenly insecure, as if there were no longer any ground under our feet. But that is not the case.
There is as much — or as little, depending on your point of view — ground under our feet when we
are considering a moral question that turns on a vague distinction, as with all the other judgements
concerning vague distinctions that we confidently make every day of our lives.

Geoffrey Klempner