Can you please point me to philosophical discussions of intelligibility or of what counts as intelligible? — or to an accepted intelligible view of intelligibility, if there is such a thing (pun intended).

I was surprised that I have failed to find anything satisfying with Google. See for example the SEP article on The Principle of Sufficient Reason. This is how it opens:

The Principle of Sufficient Reason is a powerful and controversial philosophical principle stipulating that everything must have a reason, cause, or ground. This simple demand for thoroughgoing intelligibility yields some of the boldest and most challenging theses in the history of philosophy.

However, while the article employs the term intelligibility several times, I have found no discussion of what intelligibility means in SEP.

Most dictionaries define intelligible roughly as able to be understood, but as we all know we poorly understand what it means to understand.

I have been quietly using intelligibility in the sense given by Chomsky in On Nature and Language:

The galilean model of intelligibility has a corollary: when mechanism fails, understanding fails.

That is, what cannot be understood mechanically, cannot be considered intelligible. For example, Newton's theory of gravity is an intelligible theory (it is a collection of simple formulas that a computer can work through), but (Newtonian) action at a distance which underlies the phenomena of gravity is itself unintelligible, as pointed out by David Hume:

While Newton seemed to draw off the veil from some of the mysteries of nature, he shewed at the same time the imperfections of the mechanical philosophy; and thereby restored her ultimate secrets to that obscurity, in which they ever did and ever will remain.

But provoked by a recent discussion I am looking for philosophical discussions of intelligibility. Any pointers and insights would be welcome (but please no home-made half-baked out of the sleeve ideas).

  • Good historical reference: Petr Dear, The Intelligibility of Nature: How Science Makes Sense of the World. Intelligible=understandable; no way to define all. Commented Oct 6, 2017 at 13:49
  • The point of Chomsky's statement is that the "criteria" for understanding change in time, with the development of science and philosophy. Commented Oct 6, 2017 at 13:50
  • Maybe useful: von Wright, Explanation and Understanding. Commented Oct 6, 2017 at 13:54
  • @MauroALLEGRANZA, It seems to me that while they may be closely related, nevertheless understanding and intelligibility are not generally considered to be identical. Also I disagree that Chomsky's point is that criteria for scientific understanding merely changed over time. I believe that his point in that and other papers is that reality is ultimately mysterious or unintelligible, or beyond human capacity to reason, or fully comprehend. Chomsky is a mysterian.
    – nir
    Commented Oct 7, 2017 at 6:30
  • However, the reference to Peter Dear is good. Could be made into an answer.
    – nir
    Commented Oct 7, 2017 at 11:47

1 Answer 1


The original meaning of "intelligible" was of that apprehended by the intellect as opposed to the senses, for example Plato (in Latin translations) talks about intelligibles (forms) vs sensibles (things), see Karl's Plato’s Two World Theory, and Aristotle's use is similar.

In more recent philosophy there are two somewhat different meanings of "intelligible", both distinct from the traditional one (although inspired by it). For example, Creighton in The Form of Philosophical Intelligibility writes:

"We habitually assign to philosophy the task of "explaining" the world, or of rendering experience "intelligible"... It would seem necessary to understand as clearly and definitely as possible what type of explanation philosophy may properly be expected to furnish before any discussion is in order regarding its competency to fulfill its task, or concerning the relative value and pertinency of various systems."

This reading links intelligibility to explanation, and on explanation there is of course also a long philosophical tradition. Aristotle's four causes were originally construed as four ways to answer "why" questions, i.e. they are more properly translated as reasons or explanations. Only one of them, the efficient cause under which mechanistic explanations fall, was retained by modern science as fundamental, and eventually "cause" came to be identified with what Aristotle called "efficient cause", with additional twist that such causes are also assumed to be governed by (often deterministic) laws. Modern philosophical naturalism largely adopted this outlook, but with a revision. Even in modern physics mechanistic explanations are insufficient, Chomsky's view was abandoned there along with classical mechanics, and replaced with a more general paradigm of (efficiently) causal explanation. On the other hand, this is perhaps why many people still see quantum physics as not sufficiently intelligible.

Evolutionary explanations in biology are often teleological rather than causal (physiological traits are explained by being advantageous in species' environment, for example), corresponding to Aristotle's final causes, but such explanations are usually seen as derivative from efficient ones via the mechanisms of mutation and natural selection. The fundamental priority of causal explanations depends, however, on the success of the reductionist/physicalist programme, which in philosophy of mind is controversial, see Is there a causal influence of the mental on the physical? Modern philosophical theories of scientific explanation are well-covered by both SEP and IEP. The Friedman-Kitcher unificationist theory is perhaps the most popular, in Kitcher's summary:

"Science advances our understanding of nature by showing us how to derive descriptions of many phenomena, using the same pattern of derivation again and again, and in demonstrating this, it teaches us how to reduce the number of facts we have to accept as ultimate."

A somewhat different meaning of "intelligibility" puts emphasis not on explanation but on meaningfulness (the two are obviously closely related), "intelligible" is that which meets the conditions of the possibility of being meaningful. Traditionally, such conditions would include logical laws, like identity and non-contradiction, famously challenged by Hegel, and on some accounts even the principle of sufficient reason, although its inclusion is rare today. The prominence of this view can be traced to Kant's "conditions of the possibility" of experience or knowledge, and his employment of these notions in transcendental arguments.

Aside from the positive use, where such conditions help analyze the structure of our cognitive faculties, our "intellect", Kant effectively coined a new type of philosophical argumentation, where a view is argued to be not even false, but worse, unintelligible, because its notions violate some conditions of meaningfulness. For instance, according to Kant, the notions of traditional metaphysics are unintelligible because they attempt to apply categories of experience beyond any possible experience, to things in themselves. Such approach was since used by many prominent philosophers whose positions are very far from Kant's. For example, Wittgenstein argued against private sensations and languages because such things have no criterion of correctness required for their intelligibility, see Did Wittgenstein consider the possibility of a private language with public content? Similarly, Putnam in Realism and Reason criticized (metaphysical) realism positing "mind-independent" reality expressed in mind's concepts that "correspond" to it as unintelligible:

"But it is unintelligible, from my point of view, how the sort of relation the metaphysical realist envisages as holding between a sign and its object can be singled out either by holding up the sign itself [Cow], – or by holding up yet another sign, thus [Refers] – or perhaps – [Causes]... One of the puzzling things about the metaphysical realist picture is that it makes it unintelligible how there can be a priori truths, even contextual ones, even as a (possibly unreachable) limit."

  • What is "Chomsky's view" that "was abandoned there along with classical mechanics" ?
    – nir
    Commented Oct 7, 2017 at 6:33
  • Why do you say that "many people still see quantum physics as not sufficiently intelligible"? the physics is perfectly intelligible (some say even simple). It is the underlying reality that quantum physics describes that is ultimately unintelligible — for example its non-locality.
    – nir
    Commented Oct 7, 2017 at 6:37
  • In Philosophical Investigations Wittgenstein does not seem to use the term intelligibility in its problematic sense. He uses it twice in the private language comments, and both uses seem unproblematic, or idiomatic — a language being intelligible by a listener or not — see comments 207 and 261 there.
    – nir
    Commented Oct 7, 2017 at 7:03
  • Putnam is using the term intelligible in several places in his paper but he never explains what he means by that.
    – nir
    Commented Oct 7, 2017 at 7:10
  • There is a nice paraphrase in Creighton's paper of "Lord Kelvin that he could understand a theory only when he was able to represent it in a drawing", but otherwise I find his paper rather obscure: "But philosophy in its own domain has no concern with the bare form of existence. To achieve the form of intelligibility at which it aims it is indeed necessary that the mind shall understand the truth that is contained in this abstract standpoint, but it has also to free itself from the domination of existential imagery in order to rise to freedom and universality" — good luck making sense of that.
    – nir
    Commented Oct 7, 2017 at 9:14

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