An analytic sentence is one which can be seen to be true by virtue of the meanings of its terms. An example that is often given is:
- A bachelor is an unmarried man.
A widely held view, among academic philosophers, is that analytic sentences are tautologies. I disagree with that assessment. I am not saying that the philosophers are wrong. I am just expressing my disagreement. Maybe we don’t have the same idea as to what “tautology” means.
It is widely agreed that language is conventional. That is to say, there are social conventions that underlay language. That different societies have different languages points to this conventionality.
Among the various conventions, there can be syntactic conventions which set how words should be arranged in sentences. There can also be semantic conventions, which set the meanings of words. And, of course, there can be mixed convention that combine both syntactic and semantic aspects.
To my way of thinking, a tautology is a sentence that is true by virtue of syntactic conventions. But once we bring in dependency on semantic conventions, I don’t think we should use the term “tautology.”
Iowa and Illinois
Here’s an example.
Apparently there is an agreement between the states of Iowa and Illinois, setting the boundary between the two states as the Mississippi river (the center of the Mississippi river). According to that agreement, we can say “Iowa is to the west of the Mississippi.” From my perspective, that sentence looks analytic but I would not consider it to be a tautology.
The agreement between Iowa and Illinois is something that I would consider to be a convention. But it is not a syntactic convention. It is part of what defines the meanings of “Iowa” and “Illinois”.
Bachelors
Lets return to the earlier example, “A bachelor is an unmarried man.” It could be that there is a syntactic convention that where “unmarried man” appears in a sentence, it can be replaced by “bachelor”. If if there were such a syntactic convention, the we could call that sentence a tautology.
I doubt that there is such a syntactic convention. It seems to me that “bachelor” is normally used when talking of lifestyle, while “unmarried man” is normally used for discussing legal status. Those differences in usage argue against the idea that this is matter of syntactic convention.
Why it matters
Some creationists point to the Darwinian slogan “survival of the fittest” and they claim that is a tautology. Because of this they assert that the entire theory of evolution derives from a tautology, so it could not have any actual scientific content.
A similar claim could be made about Newtonian science. Newton’s F=ma is pretty much the definition of force. So F=ma can be seen to be analytic. If analytic statements are tautologies, then Newton’s mechanics is derived from a tautology. And that seems absurd.
Propositions
Philosophers like to talk in terms of propositions, rather than in terms of sentences. In a proposition, one is supposed to assume that a term is, in effect, replaced by its meaning.
Take a sentence of the form
- X means y
where X is just a simple term, and y is perhaps an detailed explanation of the meaning of X.
If we treat that sentence as a proposition, then we are supposed to treat it as if it said:
- y means y.
And, of course, expressed that way, it would be a tautology.
I wonder whether the idea that analytic sentences are tautologies is an artifact of looking at sentences as if they are propositions.