The Grounding of Logic

General Philosophy
161

I agree that I may experience a red postbox and have direct apprehension of it.

But then, I also may experience a headache and have direct apprehension of it.

Does it logically follow that headaches exist outside of being experienced or directly apprehended?

162

Your headache must exist in your brain. Not outside of your mind.

But you can directly apprehend it even with more intensity due to its existing in your brain.

163

You experience and directly apprehend both a headache and a red postbox.

Both my experience of a headache and my experience of the colour red have the same intensity within my mind.

Why “must” the headache exist in the mind and why “must” the red postbox exist outside the mind?

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Your headache is your perception of the actual physical event happening in your brain.

The red postbox you are seeing is a visual representation you are having in your mind caused by the actual red postbox in the real world.

The headache is caused internally in your brain. The image of the red postbox is caused internally by the red postbox outside your brain in the real world.

If someone went and painted the postbox green, then your perception will be caused by the green colour, and you will be seeing a green postbox.

Perceptual experience can be caused by internal and external sources.

165

Excellent question ! And we can talk about your headache. And your headache is no more “hidden” in a “non-logical qualitative sense” than the way that mailbox shows itself to you, with the help of your eyes.

But more relevant to the OP, a particular inference is “valid or not” according to someone. I mean it is “universally valid or not” according to someone. A mathematician can judge that a proof is flawed in terms of community norms, but this judgment involves a personal sense of those community norms.

This doesn’t make the norms “unreal.” Indeed, they are presupposed as “real” when we make a judgement about or in terms of them. But this does make them “perspectival.” At least from over here it does.

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How does one know that the red postbox exists outside the mind when all one’s knowledge about the red postbox has derived from the mind?

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Of course there has always been the opposite move of simply denying that anything exists outside of the dominant “container.” So, when the container is the mind, you get subjective idealism. When the container is language (as if democratization resolves all the metaphysical issues with the former), you have the response of “there is nothing outside of interpretations.” Or all is the plain of immanence, or all is culture, representation, etc.

With Davidson, we resolve the anxiety of being trapped in the linguistic turn, yet not by transcending language, but rather by totalizing it. Something like: “don’t worry, we aren’t trapped in a prison because there is only the prison”—as if the various rebellions against Enlightenment flattening (romanticism, the turn to Indian thought, etc.) were primarily concerned with exteriority for its own sake.

But there is a substantial difference between the idea of a coherent, interpretable web of sentences (in which meaning comes to be epiphenomenal), and an ontic ground, the Good, to which the soul is progressively conformed, etc., and we face the same disconnect here.

Proposed by who? This is no doubt a very popular view in 20th and 21st century thought.

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168

You are not just seeing red pbox. You are also seeing distance and space, which is supplied via direct apprehension along with pbox image.

Distance and space is always outside of your mind, which is part of the object you are seeing.

169

If we reason and debate about anything, then we presuppose that it is “between us” in a “logical” sense. So we can discuss your headache, because that headache is in “the space of reasons.”

Philosophy, science, and even ordinary conversation enact the presupposition of a mostly shared world and a mostly successful co-referring to entities in this shared world, enact the presupposition of mostly shared inferential norms. For Brandom, philosophy is a matter of making this enactment explicit. “Foregrounding” what is usually in the background allowing the show to go on in the first place.

For instance, you ask/challenge me to justify the claim that “the postbox exists outside the mind.” Given your assumption that knowledge is derived from the mind. Which you expect me to share as “obvious” or “given” ( but I don’t.) So you already enact a “faith” in my existence, presumably as someone “outside of your mind,” and also as “one of us,” in the sense that you grant my sensitivity to norms that bind us both. You might say that you know me “through your mind,” but direct realists will grant that your nervous system is necessary. I need my eyes to see you and my ears to hear you, but it’s you I hear. Or we aren’t having a conversation.

In short, all conversation presupposes that we are talking about somehow-shared objects. Personally I don’t like the “internal/external” framework. Basically “from-a-point-of-view-ness” or “perspectivity” gets misread by the tradition in terms of something “internal.” The myth of “user interface icons” is persistent and assumed, but the case for it is incoherent — for reasons mentioned above and others — and it is “alienated” from the way we live, a sort of “lie” in relation to who we mostly are — eating food and not internal images of food, talking to friends and not to images of friends, walking around furniture and not internal images, etc. Even talking to someone via videocall is talking to them “through” that videocall, just as seeing them in person is “through” (by means of) the naked eye. Selfhood is a temporal-normative institution at the foundation of rationality. No norms without those enacting their constraint. Also: no others, no self. The concept of philosophy “implies” (tacitly at least) that the world is essentially a forum, a space of and for assembly.

170

I ask myself : why this dominance of the container metaphor ?

“Only the other is contained.” Containment is relative, an accusation from “beyond” that container.

I mean that I can see Joe as “stuck in” certain presuppositions. He can be stuck in the container of assuming he is stuck in a different kind of container, his own “mindstuff.” So weirdly he is contained in what he might want to call mindstuff, but I might call an optional comportment performed as necessary.

For Gadamer ( as you may well know), we obtain self-knowledge and knowledge of the object simultaneously. In my confrontation with the object, I discover my initial “false containment” of the object. I was myself contained by this prejudice, which is only “visible” through this very confrontation. So I move onto to my second “false containment” of the object, and so on.

171

We have direct apprehension of distance, but this direct apprehension is direct because it is inside our mind. The question remains, how does one know this distance is outside the mind when all one’s knowledge about this distance has derived from the mind.

172

That would account for the form. How would you account for the content?

Logical formalism is deeply flawed. Content consists of what is indeterminate, so formalism attempts to exclude content in order to produce a higher degree of certainty. However, the nature of the world and reality in general, is such that content with its indeterminate nature, cannot be excluded.

Since the indeterminacy of content cannot be avoided, the result of the formalist approach is that the indeterminacy is incorporated into the formal structure, inhering within, instead of being segregated to a separate category. This has the opposite effect to what is desired, as uncertainty permeates throughout, contaminating and corrupting the entire formal structure. The indeterminate lies concealed within, unidentifiable as such, because the distinction between content and form, which isolates it, has been rejected.

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173

Yes, well in a nutshell this seems to be the bifurcation we see in every second thread. I was hoping just to stick to the grounding of logic, but here it is again and, of course, it’s related. That said, I actually enjoy any discussion that gets down to different accounts of meaning.

Do you ever get tired of having the same discussions? Does any of this really matter? Are you here to advocate for your beliefs or to win arguments? I ask simply because philosophy has almost no presence in my world outside of here, and I have minimal understanding of what propels people’s interests in the subject.

174

As you say, i) “then we presuppose that it is “between us” in a “logical” sense”, ii) “So you already enact a “faith” in my existence” and iii) “The concept of philosophy “implies” (tacitly at least) that the world is essentially a forum, a space of and for assembly”.

I agree that I presuppose that we are having a dialogue in a shared world, I have faith that this is the case and this is what my belief in Indirect Realism implies.

The OP asks “Does logic reveal something about the structure of reality itself, or is it better understood as a human tool shaped by our contingent cognitive and linguistic practices?”

But presupposing a reality external to our cognitive and linguistic practices, having faith in such a reality or implying such a reality is not knowledge that such an external reality exists.

Through our feelings and logical reasoning we may presuppose an external reality, have faith in such a reality and imply such a reality, but our feelings and logical reasoning say more about our our cognitive and linguistic practices than about any external reality that may or may not be underpinning them.

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I’m expressing this in the Timaeus thread, and I hope you join us there. ( I don’t want to derail this excellent thread. )

176

This “our” is the “essence” of “externality.”

177

Sometimes I want to advocate for a position. Here I am just reaching for an example I am familiar with. I suppose I could have used Luther or Yang Wangming as easily.

But the grounding of logic, or more broadly of mathematics, causality, and explanation, is one of those topics that is so broad I think it invariably comes around to code metaphysical issues.

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178

Many people in this world are able to conceive that ghosts exist, that a god created the world in seven days, the world is flat, there was no moon landing in 1969, the Earth was created between about 10,000 and 6,000 years ago, men can be women, that photographs steal souls, that particles can emerge from a quantum vacuum and that planting should follow the phases of the moon.

It should not be too difficult to conceive of a world where adding one to four results in three.

It is certainly the case that the physics of a possible world where adding one rock to four rocks results in three rocks is breath-taking, and incoherent within our world, but not incoherent within a world where this happens to obtain.

Philosophy should look to science.

You find it incoherent that something may cease to exist, yet in this world it is commonly accepted in quantum mechanics that not only may something exist in more than one place at one time but also that something may appear from nowhere.

For example, within contemporary science is the Mathematical Universe Hypothesis (MUH) where different worlds possess different mathematical structures (Wikipedia - mathematical universe hypothesis)

Max Tegmark proposed that our physical reality is not just described by maths, but is maths itself. In this view, such a mathematical structure of physical reality would be independent of human thought. Every consistent mathematical structure would then correspond to a unique, physical world in a parallel universe. If 4 + (-1) is a consistent mathematical structure, then it is possible that in a parallel world, the addition of something to four would result in three.

It is a truism that the physical laws we know are those laws we know about. We know adding one to four results in five because this is what we have observed, but may be explained anthropically, in that if it was otherwise, there would be no one around to know.

The physics of the MUH may be breath-taking, but would be a mistake to say incoherent.

179

The knowledge you have in your mind gets replaced with the contents of perception coming in from outside real world. In Kant, it must be your apperception (the perception on perception) which can tell the difference.

In Hume, your impressions of red pbox coming into your mind from outside has much vivacity and force. The ideas of the red pbox you already have in your mind are weaker copies of matching impression.

The difference betwixt your impressions and ideas in their vivacity and force should allow you to tell difference betwixt outside existence and the copies in your mind without getting mixed up inbetwixt the two.

180

Yes, as an Indirect Realist, I am presupposing, have faith in and implying that there is an “our”, that there is an “externality”.

However, the essence of “externality” does not depend on the existence of humans, certainly not on there being an “our”.