A brood comb

….philosophical and other notes….

Archive for June 21st, 2006

Are hedgehogs small spiny animals?

Posted by Tanas Gjorgoski on June 21, 2006

Consider those four sentences:

1. Hedgehogs don’t have spines.

There are (at least) three different things which can be meant by this sentence. One possible meaning is that hedgehogs were small animals which had spines, but which lost their spines. If someone is to say to me -Look, hedgehogs don’t have spines! it is most likely that she is using the sentence in this meaning.
Also, this sentence can mean that what we thought were spines, were in fact something else; it might be that, for example, biologically spines have some precise definition, and what we call “spines” in hedgehogs don’t fall into that category.
The third meaning is the one in which I want to consider the sentence, where the person uttering it is claiming that the hedgehogs are and were animals which don’t have spines.

2. Hedgehogs are enormous.

As in the previous case, there are at least three things which can be meant by this sentence. One is where the sentence is meant to inform us that hedgehogs have grown enormous. Or, someone can consider the issue of size of the hedgehogs relatively to the size of the atoms for example, and utter this sentence in that meaning. The third kind of meaning of this sentence is where the writer claims that hedgehogs are and were enormous animals. I take it here in this third meaning.

3. Hedgehogs are not animals, but like rabbits (in Putnam, Is Semantic Possible) they are robots controlled by Martians.

4. Hedgehogs are not material things, but they are massive hallucination induced by Martians.

First notice that all of those sentences speak of the same thing – they speak about hedgehogs. The sentences assume that people who read them will understand what is meant by that word and that by those sentences it is posited that those same things (hedgehogs) happen to be respectively: without spines; enormous; robots controlled by Martians; or massive hallucination induced by Martians.

Now let’s consider how we, the readers of those sentences, can understand them, if we are supposed to believe that the sentences are true. I will in this post analyze the first two sentences, and analyze the later ones, well… later.

In the first case, if someone utters the sentence “Hedgehogs don’t have spines” there are two possibilities me as listener I can conceive of (ignoring the alternative meanings which were discussed): either it can mean that what I thought were hedgehogs are not called hedgehogs; or that the person is using word “hedgehogs” to refer to some other things, which are not hedgehogs.
And the second sentence brings the same possibilities. If someone is to say to me that “Hedgehogs are enormous”, it is either that what I thought were hedgehogs are not in fact hedgehogs, or that person is using the word “hedgehogs” to refer to different things.

So, in the sentences (1) and (2), we see that one can acknowledge actually just one possibility, and that is that the person is not talking about things we think about when we mention hedgehogs. Or, from other point of view we can formulate this as a principle:
There can be sentences about specific word, that show clearly that the person which claims that those sentences are true, is not talking about the same concept we mean by that word.
This gives us possibility to notice a misunderstanding.
Consider this conversation:

A: My mother cooked two hedgehogs for dinner today, and whole family had very good dinner.
B: Wait, your mother cooked hedgehogs? Are we talking about same animals, the small spiny ones?
A: Oh, no, no… Hedgehogs… You know those big, flying animals.

So, let’s go back a little, and try to check once more what happens here.
A person utters the sentence “hedgehogs don’t have spines”.
We believe that person is saying the truth and we try to make sense of the sentence.
With additional questions we figure out that the person doesn’t mean to say that hedgehogs have lost their spines, or that things on hedgehogs that we call spines don’t satisfy some biological definition of spines.
After the person negatively answers those attempts from our side to make alternative sense of the sentence, we are left with not much choice. We have to conclude that the person is not talking about the animals we call hedgehogs. By the word “hedgehogs” the person is referring to different concept.

If “doesn’t have spines” (in its specific meaning) is enough to figure out that the person is not talking about our concept of hedgehogs, we should be inclined to suppose that “having spines” belongs to the core of the “hedgehogs” concept . But on the other side, it is easy to give examples contrary to that conclusion. We can imagine a hedgehog without spines. In fact hedgehogs can loose their spines when under extreme stress or sickness. Enormous hedgehogs are also imaginable, like in Monty Python’s sketch about Piranha Brothers:

Interviewer: Was there anything unusual about him?
Gloria: I should say not. Except, that Dinsdale was convinced that he was being watched by a giant hedgehog whom he referred to as ‘Spiny Norman’.
Interviewer: How big was Norman supposed to be?
Gloria: Normally Spiny Norman was wont to be about twelve feet from snout to tail, but when Dinsdale was depressed Norman could be anything up to eight hundred yards long. When Norman was about, Dinsdale would go very quiet and start wobbling and his nose would swell up and his teeth would move about.”

But then, if something which is a hedgehog doesn’t have to be spiny or small, how can we know that the person from sentences (1) and (2) isn’t talking about what we mean by ‘hedgehog’, but rather something else entirely?

There is one distinction that should be noted, which might resolve this apparent contradiction… In the “classical theory” it is supposed that concepts can be defined through a set of necessary and sufficient attributes, in such way that everything that falls under the concept will have those necessary attributes.

But here the difference is that we are not talking about the examplars of the concepts, and the attributes are not talked about as connected to the singular case, or “a hedgehog”, but to the plural – “hedgehogs”; We are considering hedgehogs collectively.

And when we think of it, it is not very hard to note that there needs to be plurality of things for general terms to be held at all. If there was just one thing, then using a general term wouldn’t make any sense, so we could use the proper name instead.
So, we can say that the plurality is central for the meaning of general terms. It is about “hedgehogs”. “A hedgehog” is just any of them.
Also plurality by itself isn’t enough, this multitude of things needs to have something in common, they need to be recognizable as have something in common. If we can’t find anything common for a set of things, there can be no reason to see them as falling in into same concept.

I will analyze the next two sentences in the next post…

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