Philosophy of languages discusses the two concepts of extension and intension. Since the 1960ies Putnam published a series of papers on topics like the meaning of meaning. He argues against the view that meaning exists in the brain only: “ ’meanings’ just aint’t in the head!” By the famous thought experiment of water on the twin earth he clarified his point of view, that the meaning of a term has to take into account more than just brain states.

In the meantime, neuroscience has established itself as a player in the domain of philosophy of mind. Some researchers with a strong capability in neurobiology and philosophy have presented new models of the mind; e.g. Gerhard Roth: Das Gehirn und seine Wirklichkeit. 1994 (in German).

The philosophical approach employs a constructivist epistemology. On the other hand, neuroscience emphasizes that the content of our mental processes solely results by pattern recognition and pattern processing from the net of neural activity in the brain. The brain is deaf and blind. It neither hears nor sees nor smells nor touches etc.

It is our cognitive system, which classifies the neural input as visual, auditive, olfactoric or sensual due to the brain areas where the input comes from and due to its time-related pattern. Herefrom the brain constructs a world-model with the relevant features of our environment. This world-model is permanently updated. All our perceptions refer to this model. But the model itself stays transparent. It is invisible to our conscious awareness: We perceive the inner world-model as if we had direct contact to the things from the outside world.

My thesis:

The meaning of a term is the relation between two mental structures, both of which form part of our world-model. One structure is the pattern of the term, the other is a combination of several other patterns (the intension).

In particular, all meaning is in the brain because the world-model is in the brain.

Added: What are possible objections?

  • 2
    I see an assertion, but not a direct question.
    – Dave
    Jul 21, 2015 at 16:24
  • @jowehler Thanks. I deleted my comment because I thought I had misunderstood. One possible objection may be that the total uniformity of the neocortex, both in physical construction and functional operation, may undermine the ability to identify two such mental structures as being different mental structures.
    – nwr
    Jul 21, 2015 at 19:16
  • I employ the term 'mental structure' to denote an identifiable substructure of the neocortex being in a definite state of activation. Using terms from computer science I consider it a process running in a subsystem - not only the subsystem considered as a static unit. (That's my answer to the former, now deleted comment of Nick R)
    – Jo Wehler
    Jul 21, 2015 at 19:20
  • 1
    Can you restructure your question to cut to the chase a bit sooner? Jul 21, 2015 at 19:43
  • If I am not already trying your patience... Kurzweil claims his view are well supported by neuroscience. According to his view, when I read the word cat, a number of elementary substructures interact across a few different layers of the neocortex to enable me to identity each letter. These composite substructures then form a unified hierarchy which enables me to understand the meaning of the word. Forming this hierarchy introduces new interactions into the ensemble but is not a separate structure. Odds are, I've probably misunderstood by Kurzweil and yourself!
    – nwr
    Jul 21, 2015 at 20:13

2 Answers 2


If you are asking is the meaning in your head all in your head, then of course the answer is yes. (I'm going to leave aside the details of your formulation, because it is specific to a degree that goes beyond what can be validated with present-day neuroscience.)

But that misses the point of the twin-earth thought experiment. I don't think it's the best thought-experiment, but it's widely known, so let's go with it for now.

In brief, suppose there is a twin earth where everything is identical and functions identically at a superficial level but where H2O is absent and there is a substance XYZ instead (which everyone there calls "water").

Now, in a sense, "water", being all in the head of both Earthlings and Twinlings (let's call them), are exactly the same thing, because they are the same thing-to-them. In particular, their mental states might be completely indistinguishable from each other, and thus we'd say that the meanings are indistinguishable.

But in another sense, they are not the same because the substances are distinguishable (though not presently to Earthlings and Twinlings) and Earthlings mean H2O and Twinlings mean XYZ. And this is a very important sense of meaning since we have to interact with the outside world. We expect that meanings like those conveyed by "water" will attach naturally to whatever additional things we find out about water including whether it's actually H2O or XYZ.

So after considering Putnam's argument one can accept your thesis and yet want more, which is to also have a theory of how many different brains can refer to the same (and/or different) external entities. The purely internal account makes that exquisitely difficult.

(Yes, you eventually have to get there by considering how the models built by your brain end up with an expectation of various invariants including that XYZ isn't quite what we mean by "water", but adding that extra layer of interpretation makes the logical structure harder to see.)

  • All agree that meaning is a semantic relation between a term and something which is in question. My point is: The semantic relation resides completely in our brain. It is a relation within our world-model. But in addition and first, there is a causal relation. It relates the real-world things of our environment to the input of our sensory organs. This physical relation has no semantics. The semantics originates when our brain detects and stores in memory certain recurrent patterns from the time-related neuronal input.
    – Jo Wehler
    Jul 21, 2015 at 21:43
  • Semantics is the result when transforming the physical relation into a relation of the world-model. Hence I consider Putnams Ansatz a bit outdated, because he does not discriminate between the two relations. I agree, that the cloned observers on earth and on twin earth construct the same world-model, i.e. they are in the same psychological state – in Putnams words. And concerning the causal relation, Putnam may also assume that the two different liquids on earth and on twin earth affect the sensory organs of both clones in the same way.
    – Jo Wehler
    Jul 21, 2015 at 21:44
  • After disentangling accordingly Putnam’s thought experiment in two quite different relations, is there a remaining problem? But probably you can expand a bit your second to last and your last section.
    – Jo Wehler
    Jul 21, 2015 at 21:44
  • @jowehler - Semantic relations may reside completely in our brains, but how they get there? Our brains are good at picking up external cues and translating them into internal semantic relations (and this happens reliably across people), so in some sense the real relationship is the external one and what's in our brains is just the details of what we need to do to notice the relationship. Then one has to ask which words one wants to use to mean the internal implementation details vs. the external relationships--Putnam seems to favor "semantics" covering the latter as well.
    – Rex Kerr
    Jul 22, 2015 at 19:03
  • 1
    @jo wehler I am afraid that language is a social game, and "meaning" as normally used is inherently intersubjective. Why not just use "mental state" to avoid the confusion. In any case, trying to interpret it as "meaning" runs into all sorts of problems with psychologism plato.stanford.edu/entries/psychologism, anomalism of the mental plato.stanford.edu/entries/anomalous-monism and inscrutability of reference en.wikipedia.org/wiki/Inscrutability_of_reference
    – Conifold
    Jul 23, 2015 at 0:25

First, I would suggest that meaning is intersubjective; this gets away from the notion of Descartian subjectivity which is self-subsistent; requiring no other.

This is Lacans distinct contribution to modern European philosophy (through his notion of the Mirror, which is just his allegorical method of re-introducing this truth; the face of the mother, or father being the 'mirror' in which we see ourselves; where we resolve a Unity of Apperception at the level of subjects; not of sensations - a la Kant).

(Unger takes this further, he grounds freedom in this acceptance).

In this picture, Crusoe on his isle, alone; would not survive for twenty years to return to the life-world; but his unity as a subject would dissolve; one cannot say disrupt; as nothing has acted on him to disrupt him; unless one goes along with Sartre (in Nausea) and say pure nothingness can act in this way.

In a different tradition, say Native Americans; aloneness is not the conditions for nothingness, as such; but to enter into a different dimension of being; the spirit world (see Black Elk Speaks). A parallel here might be with Rilkes Sonnets to Orpheus:

There rose a tree! O pure transcendence!

O Orpheus sings! O tall tree in the ear!

And all was silent. Yet still in this silence

Proceeded new beginning, sign or transformation

So, we can say meaning is both in Subjects and between Subjects.

And then of course we have the very difficult question of what is the origin of Subjecivity; which pours both light and darkness on what constitutes meaning in the world.


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