Thursday, 8 October 2015

Sceptical Comments on Propositions as Abstract Entities






"You can't believe in abstract propositions simply because the French for 'Snow is white' is 'La neige est blanche'."
 

One

It's correct to argue that propositions don’t belong to a particular language or even to a particular set of languages. However, they do belong to the set of all languages (or to language simpliciter).

If propositions are abstract entities, then how do they contain (or deliver) “units of information”? Surely only sentential expressions can offer us (or contain) units of information. A proposition (like a mental image or a representation) may be a something; though it couldn’t contain units of information. It may be the ground or basis of units of information; though it can’t be a unit of information itself. Like mental images or representations, the grounds of sentential expressions can't themselves be either true or false.

Similarly, truth-conditions don’t offer us fixed and determinate units of information. However, they are the conditions (or grounds) of later sentential expressions which do indeed have truth-values (thus offer us units of information). The units of information, however, only become determinate and fixed when expressed in sentential form. The sentential expressions, in that sense, actually produce (or offer up) units of information and they determine truth-values.
 
Two


Can the content of a statement be separated from the form of the statement? What sort of being and identity does a proposition have before it finds itself iexpressed by a statement? Do we ever have the propositional content of a statement before the statement itself? (Propositions are sometimes said to be the "contents of truth-evaluable statements".)

In

“The sentence ‘Snow is white’ is true iff snow is white.”

the snow is white in single quotation marks and italics (on the right side) isn't a proposition: it's the truth-condition for the antecedent sentence. Propositions, on the other hand, are believed to be either true or false. They tell us something that is or isn't the case.

In the past there have been many candidates for the role of a proposition (some of which, admittedly, were variations on a theme).

For example, are propositions the meanings of sentences or their Fregean “Thoughts”? Are they the denotations of sentences? Or, the current popular choice, are they the “set of possible worlds” which make a sentence true?

Again, it can be accepted that propositions may be distinguishable from particular sentences; though not that they can exist separately from all sentences. And if they necessarily require sentences to be the propositions they are, then perhaps propositions shouldn't have been given so much (as it were) kudos in the philosophical tradition.

Prima facie, it seems fairly easy to accept that the following sentences express the same proposition:

i) "Prime Minister David Cameron is a liar."
ii) "The current incumbent of Number Ten is known to tell lies."

However, even here we can say that they aren't exact equivalents. And that difference isn't all down to differences in wording. Thus if two different sentences (in the same language) can't be exact equivalents, then perhaps it's incorrect to say that they “share a proposition”.

Despite that, it can be said that i) and ii) above are simply sentential synonyms (as two words can be). When we say that i) and ii) are the same proposition, we mean that ii) is "simply the uttering of a synonym". Or if i) came second, then that would be the uttering of a synonym. (It need not be "clearer", as Quine said - simply different.)

Thus it's the synonymous (or near-synonymous) nature of two or more sentences that makes us think in terms of propositions. They do indeed – nearly? - say the same thing; though not because they share the same proposition.

Take i) and ii) again. We can say that they express the same proposition: that of Cameron telling lies. Can that proposition escape all sentential expressions?

It can be argued that sentences (or minds through sentences) individuate and determine the facts or states of affairs. The fact of Cameron telling lies is a gerrymandered entity. That is, what he does before he tells lies, what he does after he tells lies, the events and people which surround Cameron when he tells lies – all these are erased to create the determinate entity that is a statement.

It's not being said that Cameron telling lies or snow's being white only exists as a statement. It's the individuating that's sentential and therefore a product of minds. The concrete and abstract things which make such statements true all exist independently of minds. However, the statements which capture such things are clearly not independent of minds.

Again, it all depends on what people mean by the word "proposition".

It can be admitted that what constitutes a statement (facts, truth-conditions, abstract objects, sets of possible worlds... take your pick) exist separately from all sentences; though not the proposition itself.

Books can exist separately from libraries; though when they are brought together, they constitute a library. Nonetheless, a single book isn't a library. Similarly, many mind-independent things may be necessary for statements; though only these things plus sentences (as well as minds) are sufficient for statements which are seen to have propositional content.

This is what makes the metaphysical realist make a fundamental mistake.

Many of the constituents of truth, truth-conditions, propositions etc., for example, may indeed be “mind-independent” (or abstract) and therefore separate and separable from sentences. Realists therefore conclude that truth, truth-conditions, propositions, etc. are separable from sentences (as well as minds).

Is an "abstract object" (i.e., a proposition) non-spatiotemporal or simply mind-independent (or both)? If it's non-spatiotemporal, how do we gain causal access to it?


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