Informally, we could collect a number of statements, propositions, assertions, or facts which are ideally in a purest, most elementary or fundamental form. For example, instead of leaving belief in the theory of evolution by natural selection up to a subjective, open-ended process of reading, observing, and considering, we could try to make it as organized and structured as a mathematical theory, in some way. We could list the absolute starting premises of which we are most certain - akin to axioms - and create a dependency graph of propositions which follow from those axioms. There could be a degree of likelihood in each graph edge to point out which parts of the theory are uncertain or not fully developed.

In other words, has anyone tried to formalise (to whatever extent possible) more complex, conceptual, even humanistic domains of thinking with some relatively rigorous system, more akin to mathematics, as opposed to theorising in a free form way?

In such a system, how could the elementary propositions be given criteria to ensure they are “elementary”? I think any concept used - like, “animal” - would have to have a strict conceptual model on hand, so that it could be verified that the definition of the term was a precise model corresponding to something in reality.

(We could also then ask ourselves what percentage of such “facts” are estimated to be known in a scientific field, i.e., how much of the model of the brain’s functioning we clearly have identified, how many rules of the total system are yet unknown.)

Put another way: is there any attempted framework for “proof” outside a mathematical context, determining the meaning and veracity of real-world propositions with linguistic concepts, in a systematic, structured and rule-based way, like “the train is late”?

  • 4
    This project was tried in 1930s by logical positivists, but failed and was largely abandoned after Quine's and Kuhn's critique. The problem is that there is no "purely observational" language to express "facts" and build bottom up from there. The meaning of all terms and the truth of all facts depends, in part, on theoretical presuppositions, supposedly up the chain. This is known as theory-ladenness of observations. Moreover, observations must be combined with value judgments to produce theories, which are value-laden, see SEP.
    – Conifold
    Commented Oct 30, 2021 at 12:16
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    – J D
    Commented Oct 30, 2021 at 17:15
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    As is often, Conifold summed up. I'll expand on his ideas later tonight by talking about some of Hempel's contributions.
    – J D
    Commented Oct 30, 2021 at 17:16
  • @Conifold It’ll take me some time to appreciate that SEP article. Why is there no purely observational language? If the world objectively exists, why can’t it be described in clear concepts mapping to existing things? Reason or inference is harder; I believe laws of inference are excavated only through trial and error; laws of physics exist only tentatively, in the absence of contrary evidence. We will never have a proof that an everyday logical deduction/implication/inference is correct; these things are only extensions of, expectations of the mechanisms of the world we are familiar with. Commented Jan 31, 2022 at 22:10
  • I remember Geoffrey Pullum quoted Nelson Goodman saying roughly this last thing about how laws of inference or of reality have only ever been discovered empirically. Commented Jan 31, 2022 at 22:16

2 Answers 2


Short Answer

[I]s there any attempted framework for “proof” outside a mathematical context, determining the meaning and veracity of real-world propositions with linguistic concepts, in a systematic, structured and rule-based way, like “the train is late”?

'No' is the currently received view on this question. This is because the notion of facts being free of normativity is largely rejected, even if one attempts to defend "objective" observations as being intersubjective. Subjective bias, theory-laden definition, and bundles of hypothesis seem to make this impossible and have raised questions regarding the incommensurability of scientific theories.

Long Answer

This is an excellent question. 'Is it possible to use math and logic to make science more rigorous is" the right impulse, one that motivated operationists, logical positivists, and logical empiricists to search for ways to squeeze certainty using mathematics and logic. It's a conversation that lasted almost five decades until incommensurability (SEP) especially by Feyerabend and Kuhn and others in the spirit of Duhem became considered endemic to scientific theory. This whole discussion is part of the larger dichotomy between scientific realists and instrumentalists (SEP).

Given the long conversation, let's grab some ideas from Hempel's A Logical Appraisal of Operationism which is contained in Aspects of Scientific Explanation. In it, Hempel attempts to compare the methods of operationists like Bridgman with ideas that Carnap, Ramsey, and others done ending in commentary involving Quine's Two Dogmas.

After examining the operational definition, Hempel comes to the conclusion that such efforts "would evidently be overly restrictive" and that it would "need to be construed more broadly" (pgs.125,126). A measured object isn't measured continuously and its characterization is thus dispositional (SEP). More importantly, he goes on to say that "observational vocabulary of science is essential to the idea of operational definition". This notion of splitting up statements that comprise a scientific theory as exclusively observational or theoretic and ruling out meaningless metaphysics was at the core of the program of the logical empiricists.

The general idea is that it should be possible to have claims in natural language become irrefutably logical and represent elementary intersubjective facts about the natural world. Doing so would form a foundation of a scientific theory and make that theory rigorous and irrefutable once verified, a doctrine called verificationism. Confirmationism was then argued to save verification. That was found to be lacking by Popper who advocated for falsificationism. Hempel:

[T]he original requirement of full verifiability or full falsifiability by experiental data has to give way to the more liberal demand for confirmatbility... [t]his demand can be shown to be properly applicable to entire theoretical systems rather than to individual hypotheses - a point emphasized, in effect, already by Pierre Duhem.

He then goes on to recognize Quine's attack on the analytic-synthetic divide.

What does this all mean? It means, to sum up, that there is no clear demarcation between the psychological and empirical, and the logical and theoretical. Or more precisely, analytic statements which are essentially objective facts cannot be cleanly differentiated from synthetic statements which are essentially semantic in nature. Observational claims are necessarily tinged by theories. This is known as the theory-ladenness of scientific theories and a pillar in arguing the incommensurability of scientific theories.

So, to recap, the drive to show it is possible to make facts irrefutable collapsed by the 1970's into discussion about is it even possible to have two scientists understand each other's theories:

From Blackwell's A Companion to the Philosophy of Science, the article Incommensurability, p. 172:

One common and natural interpretation of the idea that there is no common measure among rival scientific theories is that they cannot be phrased in a common set of linguistic terms, or, to put it more simply, that they cannot both be translated into a single language.

Quite the reversal! In prior decades, the ambition was to craft a technique for mechanizing observations and their statements, and now science found or rather finds itself struggling to explain how competing theories even are understood by opposing camps. And there are other problems raised by the Duhem-Quine Problem and related concepts like confirmation holism.

  • I’ll study these sources over time and I’d like to pose some questions to get a foothold on these matters. Why are facts inextricably linked to normativity? What really is intersubjectivity? Commented Jan 31, 2022 at 22:21
  • (cont.) Why is there no demarcation between the psychological and empirical and how does it bear on this question? What do you consider a “synthetic” statement “semantic in nature”? It will take me a long time to catch up on this reading but I’m curious above all what is hindering the assertion of any concept, like “cat”? Thank you Commented Jan 31, 2022 at 22:31
  • Heya. Uh, let's see. Facts are expressed in language, and language is normative on several levels: connotation, denotation, and context. Since language truncates experience, it captures a partial picture. A simple example is the use of active vs. passive voice. The choice and what it highlights is an expression of a value. From a social perspective, languages are public conventions and all conventions are normative too.
    – J D
    Commented Feb 1, 2022 at 19:31
  • Science is the social edifice that advocates empiricism which is the coalition from which highly conceptual facts emerge, but empiricism is an epistemological methodology that inheres to the thinker, and since all thought is psychological, the divisions between psychological and logical are somewhat arbitrary, a fact more readily demonstrable in informal logic. Analytic statements are generally easily expressed formally, so one might think of analytic statements as being amenable to syntactic expression and comprehension. For instance, algebra is highly analytical, but for some statements...
    – J D
    Commented Feb 1, 2022 at 19:37
  • they derive meaning from virtue of experience, and experience is semantic because semantic grounding is rooted in experience. As for intersubjectivity, it's just a more sophisticated understanding that in any conversation, what is deemed "objective" is relative to the society. God is objective in church because of intersubjective agreement. There are many realities, and even physicists disagree about what constitutes objective. There's no hindrance of an assertion of concept like "cat", but rather a potential disagreement about what constitutes a cat. In biology, for instance,...
    – J D
    Commented Feb 1, 2022 at 19:40

There are certainly attempts.

While there may have been interesting philosophical work done on this topic in the 20th century, I am not of the opinion that the matter is settled.

  • When you provide links, please quote relevant content and explain how they fit into the picture. Your answer is not very useful without reading the links, which may well change or go offline over time.
    – Philip Klöcking
    Commented Mar 30 at 16:26

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