Monday 26 September 2022

There Are No Abstract Propositions

Crudely, should we believe that there are abstract propositions simply because, say, the German for “Snow is white” is “Schnee ist weiß”?

One

Many philosophers and logicians have argued that abstract propositions don’t belong to a particular language or even to a set of languages. However, it can be argued that propositions (if not abstract propositions) do belong to the set of all languages — or to language simpliciter

Yet, if that’s the case, then perhaps such things aren’t propositions at all. That is, perhaps propositions don’t exist (or have being) if they’re seen to be abstract entities. (The British philosopher P.F. Strawson — some 70 years ago — suggested substituting the word “statement” for the word “proposition”.)

A proposition is often said to be a “unit of information”.

Thus, if propositions are abstract entities, then how do they contain (or deliver) such units of information? Surely only sentential expressions can offer us (or contain) units of information — at least of the informational form said to be (metaphorically) contained in propositions and which are then expressed by natural-language sentences.

Let’s concede that a proposition (like a mental image or a representation) is a… something. However, how can that something contain units of information unless that information is expressed by a sentence (or by sentences)? Perhaps it can be provisionally accepted that a proposition is the ground (or basis) of later units of information. But can an abstract proposition itself be a unit of information? Moreover, much like the mental images or representations mentioned in parentheses a moment ago, these (possible) grounds of later sentential expressions surely can’t be either true or false.

[Relevantly, Bertrand Russell believed — at least at one early point in his career — that abstract propositions were structured entities which have properties and objects as their parts or constituents. See here.]

Similarly, truth conditions and truthmakers alone don’t offer us fixed and determinate units of information. That said, they are still the conditions (or grounds) which give later sentential expressions their truth values — thus also offering us units of information. These units of information, however, only become determinate and fixed when expressed in sentential form. This means that sentential expressions must actually produce (or offer up) units of information and thus allow and determine truth values. Consequently, such units of information don’t actually have any status (or reality) as units of information before their sentential expressions. Indeed, even the aforementioned word “their” (as in “before their sentential expressions”) is incorrect because if abstract propositions don’t exist, then there can be no such thing as their expression. And that’s because this temporal position would entail a distinction between abstract propositions and their later (sentential) expressions.

[I’m not convinced about many of the distinctions which are made between truthmakers and truth conditions in the philosophical literature. For one, if truth conditions belong purely to semantics, then some of the truth conditions of specific sentences offered by philosophers and logicians certainly don’t supply what many laypersons — and other philosophers — would deem to be the meanings of those sentences… But, of course, that simply raises the issue as to what meanings are. In addition, even if a truthmaker (i.e., “that in virtue of which something is true”) is deemed to be a “parcel of reality” (or even a parcel of an abstract world), then it would still need to be expressed by a sentence (or sentences). Thus, truthmakers must become the subject of semantics. Moreover, the linguistic expressions of truthmakers also require semantic evaluation.]
 
All this raises further questions.

Two

Firstly, can the content of a (linguistic) statement be separated from the form of that statement?

Another way of putting that question is to ask what sort of being and identity an abstract proposition has before it finds itself expressed by a natural-language sentence.

So do we ever have the propositional content of a sentence before the sentence itself is constructed? (Propositions are sometimes said to be the “contents of truth-evaluable statements”.)

Take the following often-used T-schema:

The sentence “Snow is white” is true if and only if snow is white.

The words “snow is white” are in quotation marks and the italicised (on the right side) snow is white is (meant to be) the truth condition for the antecedent (in quotes) sentence.

An entire proposition, unlike truth conditions (such as snow being white), is believed to be either true or false. It tells us something either is or isn’t the case.

In the past there have been many candidates for the role of a proposition. Some of these candidates, admittedly, were simply variations upon — more or less — similar themes.

For example, is a proposition the meaning of a sentential statement?

So it’s worth noting here that in much 20th-century philosophy a “meaning” was also deemed to be an abstract (or at least non-linguistic) entity which is shared by all the natural-language sentences which were believed to “have the same meaning”. Clearly, this position is tied to the philosophical debate about abstract propositions.

Alternatively, is a proposition a Fregean “Thought”?

[Fregean Thoughts are entities “for which the question of truth arises”. Gottlob Frege himself held the view that propositions are abstract entities (or Platonic entities) which exist in a non-physical “third realm”.]

And a recent popular choice — at least from the 1970s to fairly recently — was that a proposition is the “set of possible worlds” which would make the sentence which expresses it true. (This position is said to date back to Ludwig Wittgenstein’s Tractatus.)

Again, provisionally it can be accepted that propositions may be distinguishable from particular sentences. However, a proposition can’t exist separately from all sentences. And if a proposition necessarily requires a sentence (or the set of all — synonymous — sentences) to be the proposition it is, then perhaps abstract propositions as a whole shouldn’t have been given so much kudos in the philosophical tradition.

That said, it seems fairly easy to accept that the following two sentences express the same proposition:

1) “The father of Johnny Smith is a liar.”
2) “Johnny Smith’s dad lies.”

However, even here we can say that (1) and (2) aren’t exact. Yet that difference isn’t all down to differences in wording. Thus, if two different sentences (in the same language) can never be exact equivalents, then perhaps it’s incorrect to say that they “share [the same] proposition”.

Despite that, it can be said that 1) and 2) above are simply (as two words can also be) sentential synonyms. This means that when we say that 1) and 2) are the same proposition, we mean that 2) is “simply the uttering of a synonym” of (1). Or, if 2) came first, then (1) would still be the uttering of a synonym of (2). (As Quine argued, the synonym needn’t be “clearer”, simply different.)

Does all this mean that it was the synonymous (or nearly synonymous) nature of two or more sentences which made philosophers and logicians think in terms of abstract propositions?

For a start, we can accept that such sentential synonyms do indeed — nearly — say the same thing. However, they don’t do so because they (metaphorically) share the same abstract proposition.

Take 1) and 2) again.

We can provisionally argue that they express the same proposition. Yet can the (supposed) abstract proposition (as it were) behind or underneath the natural-language sentences escape all such expressions?

On a related issue.

It can be argued that sentences (or persons-with-minds using natural-language sentences) individuate and determine the facts or states of affairs. Yet the fact of x being y has been seen to be a “gerrymandered entity”. (Philosopher P.F. Strawson called such things “sentence-shaped objects”.) That is, what Johnny’s dad did before he told lies, what he did after he told lies, the events and people which surrounded him when he did and didn’t tell lies, etc. — all these things are erased to create the determinate entity (or simply “string”) that is the statement, “The father of Johnny Smith is a liar”.

It’s not being said that x’s telling lies (or snow’s being white) only has any reality (or being) when expressed in a sentence (or sentences). It’s the individuating that’s sentential and therefore a product of human minds. It may be the case that both the concrete and abstract things which make such statements true do indeed exist independently of minds. However, the statements which capture such things are clearly not independent of minds.

Yet, again, all this depends on what philosophers, logicians and laypeople mean by the word “proposition”.

It can be admitted that many of the things which are required to make natural-language sentences true (facts, truth conditions, states of affairs, abstract objects, sets of possible worlds… take your pick) exist separately from all sentences and from all persons-with-minds. However, propositions themselves do not do so.

Consider this comparison.

Books can exist separately from libraries. However, when books are brought together, they constitute a library. Nonetheless, a single book isn’t a library. Similarly, many mind-independent things are necessary in order to make sentential statements true. However, only these things plus sentences (as well as persons-with-minds) are then sufficient for all the sentences which have truth-evaluable content.

Perhaps all this is what made propositional realists (a subset of metaphysical realists?) make a fundamental mistake.

Again, many of the (as it were) things required to make sentences true may well be mind-independent (or abstract) and therefore separate — or separable — from such sentences. Thus, because of that, propositional realists might well have concluded that propositions themselves are separable from all sentences — as well as separable from all persons-with-minds.

Finally, is an abstract proposition really non-spatiotemporal and mind-independent? Mind-independence, of course, has just been discussed. So what about propositions being non-spatiotemporal? If propositions are non-spatiotemporal, then how do we gain (causal) access to them? …

That issue is, of course, another very-familiar philosophical ballgame.

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Final Thought

The essay above is a tidied-up version of something I wrote in 2015. So I’ve been thinking about this issue for a few years (on and off, of course). I’m still not sure about it. That said, I’ve seen no convincing arguments which have shown me that my (as it were) eliminativism about abstract propositions is incorrect.

Perhaps all this simply shows that this is really a non-issue. Either that, or it’s all mainly — or even entirely — down to how each individual defines the words “abstract proposition”. More fundamentally, it may depend on how each individual defines the word “proposition”. Alternatively, it may be a non-issue precisely because it all mainly boils down to conflicting definitions.



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