Mind, body and ME

There are two possible answers. Dog pontifical cells may have undergone synaptic pruning so that they only receive dog-relevant inputs and work on a traditional summate and fire basis. What I may not explore in the Frontiers paper is just how different different types of neurons are in dendritic structure. The other possibility is that each cell randomly develops a 'sweet spot' for a particular input pattern amongst many possible patterns. (This is similar to Edelman's neural Darwinism idea, which is not actually his but was around when I was a student and he was getting his Nobel working on antibodies!) The huge number of neurones in a brain and the huge number of inputs to each suggests that in order to compute quickly we build vast libraries of cells that can pick specific patterns out of data. Some of these cells may never be called on to fire in a lifetime but that does not matter. What is more likely is that during recognition events the brain starts off allowing lots of cells to fire rather non-specifically and then sharpens the time resolution until only a score or so of cells are firing first and dictating downstream events.

 

Are you saying that a neuron can receive input and not give an output, and that the no output might mean either «No» or «N/A»?

 

What I do not include in the Frontiers paper is Aru's idea that consciousness involves both immediate sensory and prediction inputs into the same dendritic tree - top and bottom. In fact this idea has been around for a while and Steve Sevush has always favoured it but Steve does not publish much. So for some cells responding may be a matter of comparing two inputs rather than being devoted to recognising any specific input.

 

Will a neuron always give the same output if it fires? And are all outputs the same across all neurons?

 

Yes. For neurons at the level of experienced meaning we talk about I think it probably means N/A but the logic of this is very subtle and complex. There are some situations where you cannot separate No from N/A.

 

The general doctrine is that a cell has only one output option - fire. It can fire at different rates but it is hard to see how that can provide different meanings other than perhaps levels of salience or confidence of a particular statement. A cell has no way of changing the meaning of its firing but the meaning of its firing may be very dependent on what other cells are firing. I am not sure what you mean by all outputs being the same across all neurons.

 

Are there situations where you can separate them when there are no outputs?

And does a neuron have a «memory» so that two or more N/A eventually turns into a Yes?

 

That they all fire at the same «power» with the same characteristics so that output from one is indistinguishable from another.

 

I am not sure that anything 'explains' the correspondence between the physical dynamics and the sensed meaning. There just is a brute fact that certain events in neurons 'look like' a kitchen table and a smartphone for me. I think Descartes says we just have to accept that there is this correspondence. The rest of our science boils down to brute facts - like the existence of charge with two options and quark colour with three and the speed of light. I am not sure of the problem here.

 

This takes a lot of unpacking and maybe more than we can do on a forum. Are you familiar with Frege (Sense and Reference) and, more importantly, Grice? Frege didn't really get sense right in that he talked in terms of mode of presentation and there is a further sort of meaning which is just what it is like - which includes values like good and bad and phenomenal aspects like colours and smells. Grice emphasises the difference between meaning by and meaning to. He is largely interested in meaning by but works through just how much language is dependent on both coinciding in some useful way.

So I don't think there is any one 'real meaning' inputs to cells and outputs are going to have different sorts of meanings - scenarios and propositions in simple terms. Meaning shifts at every step as it goes through sequential inferences.

 

I was talking about separating no from not applicable in the abstract. For some propositions no and not specified may degenerate to the same thing.

We don't actually know what any neuron outputs mean much. There are a few experiments that suggest what they would be but very few.

Not sure what you are suggesting here. Neurons change their connections following inputs sometimes and that contributes to the memory of the brain but neurons do not have a means of remembering past inputs as events.

 

For any particular are of brain you are likely to have millions of neurons in a bank at a certain level of function that produce outputs in terms of action potential spikes that will look more or less identical to a neuroscientist measuring them. But the brain can distinguish every one of them because each one will be sending its signal to a different receiving synapse. Cell A might signal there is a green patch and its output branches only ever relay that signal to synapses at downstream neurons that are there to mean to the downstream neuronal that there is a green patch. Cell B might always send a signal to synapses that convey meaning of a blue stripe.

The importance of this, which is widely recognised by many working in the field, is that meaning has to be encoded in place of signal arrival and the spatial relation of that place to places where other signals arrive. There isn't any other way to 'carry' meaning that will be sensed by the receiving cell because, as you ask, the signal are all identical in themselves, just arriving at different places.

 

After thinking about it, I actually agree there is no explanation in this case. However, I would argue that this situation is fundamentally different from every other sense of the word ‘meaning’. I haven’t read Frege or Grice, and if you think they are important I would be happy to read them. The ‘meaning by’ and ‘meaning too’ seems to be an accurate distinction in terms of how ‘meaning’ is used so I will use that language. I apologize for what is a long post. But I wanted to take these ideas and refer them in terms of meaning in the sense of meaning corresponding to the physical system. This is fascinating and has some very significant consequences for philosophy.

I would define ‘meaning by’ as the way we use language to express how something means in terms of other meanings. In this case, every ‘meaning by’ is a tautology in the sense that if you started reading the dictionary you would ultimately always end up in some repeating cycle. Not to get into too much of a sidetrack but ‘meaning by’ is how I think science, logic and math works; explaining complex things in terms of more basic meanings.

In this sense, what is meant by the phrase " the speed of light in a vacuum is constant” relies on all sorts of explanations. It must be explained in terms of what light is, what a vacuum is, what speed is, what something being constant is. And we could keep breaking those down those terms into their constituent parts. However, at no point is there any layer at which there exists some brute fact. We would just keep going around in circles. I think this is because whatever the speed of light actually is, what its ‘true’ nature is, is completely unknowable. Any understanding of the speed of light must occur in some place that produces meaning and not in the nature of the speed of light itself. What something actually is is completely separate from what something means, and we can only know the latter of these things.

However, I think the meaning that comes from the correspondence between meaning and physical systems is far more fundamental. It is the meaning of what meaning is itself. It is every meaning that could possibly ever exist (in humans at least). All meanings, every meaning, boils down to the one (or possibly more) physical processes. We are defining a thing in terms of itself so it is the tautology by which all meaning is produced. What we actually mean by "The speed of light in a vacuum is constant" are the meanings that the neurons derive for each of these terms. There are other terms that mean similar to the above statement which we can use to explain 'meaning by' in terms of these other similar neural meanings. But since each of these neurons is not exactly the same as the corresponding neuron in another individual, meaning is also not exactly the same for different people.

The reason why we explain the meaning of things in terms of other things is probably evolutionary based on the fact we are social creatures. This process would try to get someone else’s “neural meanings” to fire if we can’t make that happen on the first try. In this way we can transfer meaning to someone by providing it to them in a form they can consume. At some level people all probably have similar “meaning too” and so using “meaning by” we can try and strip back layers until we get to some fundamental understanding. I think this would typically but doesn’t have to reside from the knowledge gained through the sense data and experience of the world.

The meaning of colours and smells is meaning in the ‘meaning too’ sense. As you said it is just what it is like to experience something. This is quite literally the meaning that the neuron provides when it gets the direct inputs of red without all the extra steps of ‘meaning by’. While it seems silly to ask what is ‘meant by’ red because the experience of red seems so obvious to us, what we really mean by red is the neural meaning of red. There must be something about how these neurons are set up that 'meaning too' seems obvious and the 'meaning by' is not.

Why we developed the idea of ‘meaning too’ might be due to the fact that everyone has experienced the red neuron firing. There are no reasons to have other neurons that mean similar things to red. What is no evolutionary advantage of explaining the meaning of red to someone else if they already know what red means. In contrast, describing some dangerous creature you saw to someone who has never seen it is very important. The person who hasn't seen the animal has no idea what neuron you are referring to. But if they can explain it in terms of ‘meaning toos’ or the ‘meaning bys’ they have experienced, then they can narrow down the possibilities for which neuron the person is referring to. By narrowing it down, someone else can have a very good idea of what neuron provided meaning to the first person without ever having had that neuron fire from the sense inputs.

I think the key question is in what ways ‘meaning by’ and ‘meaning too’ differ in terms of how the meaning is derived by the neuron. Perhaps they are the same thing and only differ in how many equivalent or similar neuronal meanings there are. Or perhaps it just refers to the number of steps there are between the sense inputs and the neural meaning, as at each step the input data is given some meaning. Or maybe there is some slight functional difference in how cells derive meaning. Or maybe a combination of all of the above.

I also have plenty of ideas about meaning in the context of values, morals and concepts of good and bad. I am an emotivist so I think your model fits very well but this post is already far too long.

 

Thank you for this. This is amazing stuff and I am honestly surprised these ideas are not more popular. I really like the cellular sweet spot theory as I can see how that could develop through evolution. I have a few questions about the last part of this paragraph and on some of your other posts but I'll ask them on another day.

 

Meaning as the correspondence with the physical also vindicates Descartes’ Cogito. The statement “I think therefore I am” has something meant by’ the terms ‘I’ and ‘think’ and ‘am’ which can not be taken as necessarily true. But if we take this statement in terms of physical processes we don’t have anything that is ‘meant by’. What “I think therefore I am” really meant was just the proclamation that for each meaning there must be some neuron producing its meaning that must exist because the meaning exists.

 

If this stuff interests you then I would strongly recommend reading Frege's Sinn und Bedeutung (but also some of the library of commentary in the 100 years since) and Grice's Studies in the Way of Words, which is transparent. Your framing of the difference between meaning by and meaning to is a bit closer to Frege's distinction between sense and reference I think, although these are Grice's terms. Grice was specifically interested in meaning in language but coined the idea of 'natural meaning'. If you look at a tree stump and see eighteen rings that means that the tree lived for eighteen years. But there is no language.

Broadly, I agree with your breakdown. Sensed meaning, or meaning to, divested of the mechanics of language, must reflect the actual physics in a neuron. But of course the meaning of 93 synapses causing local depolarisations will not be '93 synapses causing local depolarisations' but 'there is an orange on the table'. People think that is weird but of course it is not. The neuronal is not accessing the dynamics of the orange in a purely optical fashion. It is not 'seeing' an orange. It is accessing some depolarisations of the sort that our brains use to represent an orange. And there is no other 'transparent' or 'Gods eye view' appearance of an orange that we are missing. It might seem odd that we can see oranges in depolarisations but it only does because we assume this God's eye view exists.

My understanding is that the quantum field theory of biological matter provides a plausible substrate for experiencing very complex meanings of this sort. Why the coding choices are the way they are isn't really a problem. Not only may bees see circles using different physics from us, different neurons in the same human head may see colours and circles using different physics. It would not matter because that physics is never sent anywhere as a language. The next cell just interprets a spike as red because it has come in at the red place.

I am also not too bothered about our being able to sense good and bad, even if these have no immediately obvious counterpart in physical dynamics.

What is to me most mysterious thing is that our sensed meaning is at times demonstrably wrong. We have concepts that are self-contradictory. How could the fundamental fabric of matter misinterpret itself? I think this may be as misplaced a worry as the one about how we can see an orange in some potentials but I find it hard to unpack.

I understood none of this at all until my late forties and didn't start piecing things together until my mid fifties. There are a huge number of things to integrate into a conceptual framework but I do think it can be done.

Descartes should really said 'there is some thinking here, that can be sure of its presence here'.

 

This is a very enjoyable thread, thanks Jo Eddie and others for the discussion. I have too many questions and points to pick up, I'll circle back to your paper when I have the energy but in the mean time..

Agree with this. Through direct experience the classic quote 'I think therefore I am' does seem to be really wrong (though I'm maybe getting the impression from you that this quote is a misrepresentation of his arguments?). The felt sense of an observer of a moment seems to appears in a separate moment after it and also seems to tie itself to a physical sensation usually just above/ behind the eyes. You can even 'look' at that physical sensation but all that happens is the felt sense of an observer appears in the next moments tied to something else, like a sensation in the back of the head, or the jaw, or somewhere else in the body. It is possible also for a moment to be experienced without any sense of observer, but the observer feeling always gets rebuilt anyway after that. Some claim it's possible to permanently stop the observer feeling arising at all but I don't know that's way beyond my experience. (by moment i'm referring to the resolution of these slower humanly resolveable units here, not your physically indivisible conscious units)

The point though is that it seems experience is made of a stream of moments that arise and pass away one after the other, spaceless and timeless and without an observer.

The 'for me' part is then what bothers me here. If there really is no observer and just a stream of awareness, then 'my' awareness is also 'the' awareness. If there is a neuron in my brain that on its own directly correlates with the conscious concept of an orange on a table (which I think is what you're arguing unless I've misread you), this could be sort of assessed empirically right? Stimulate the synapses at the dendrites (in the right way whatever that may mean) and the orange on a table concept will arise. Take the neuron out of the brain and put it in a petri dish and do the same thing, does the concept still appear? If we go to your brain and stimulate one of your neurons encoding the same/similar concept which in terms of physics operates supposedly the same way, nothing will appear in this stream of conscious moments which terrestrially we would refer to as 'my' awareness.

It seems only fair to everyone else to assume that their neurons project consciousness too, so the activity of a neuron would produce a conscious concept of some sort which both arises and doesn't arise?

 

OK, the 'for me' there was a sleight of hand. It should really have been for that event, considered as here and now, even if to consider it we must assume it was there then!

I don't see there as being an observer other than the event of observation in a sense, but the physics account will involve a 'cause' element and an 'effect' element and I think we can call the effect element the observer.

This gets heavily into the metaphysics of field theory but as I understand it the universe is composed of fundamental events in which an existing field pattern in a space-time domain gives rise to the creation of a new 'quon' or 'field excitation'. The field pattern informs the event and the event has the identity of the quon that arises. This is what is shown in a Feynman diagram but because of the peculiar indivisible nature of the entire life of the quon the event relates both to the junction and the wiggly line that comes out of the junction that is the photon or electron mode or whatever of this event.

Things are also a bit more complicated because the quons that experience field patterns in brains that we report as 'our experiences' are likely to be higher order modes that are associated with enduring objects in the form of field asymmetries based on ordered condensed matter - cell structures. So it may after all be legitimate to call the cell structure an enduring 'observer'. Whether the experiences are a continuum or a string of pearls is hard to adjudicate on the basis of introspection for reasons we may already have covered.

It could be argued that, in fact, every experiencing event/quon exists in its own particular universe. It is just that whenever you check, universes will agree. But this gets hairy. I think we should assume that there are experiences in my brain, some of which contribute to the reporting of 'my experience' and that there are experiences in other peoples brains. The thing that most people find most difficult to handle is the idea that when I report 'my experience' my body is reporting the consensus of vast numbers of cells with equivalent content to their experiences - like an election. For each event 'me' seems to be here and now, but that does not stop there being other events with their different here's and nows.

I have so far bypassed the issue of whether the me reporting the experience is reporting the introspective judgment that there just was another experience than the one of the judgment. I see that as subsumed into an ongoing series of events that may have to be seen as discrete but may be 'co-owned' in the way described above in terms of high order quon behaviour.

 

Hear hear! I admire the ability to even follow trains of thought like this, let alone hold them up and interrogate them.

I started reading the posts, but instead of trying to grasp the concepts I went down a sidetrack about single cell organisms acting as one. When you find yourself wondering whether slime moulds or cats' immune systems have experience it's honestly time to get on with the washing up.

I really hope the discussion will continue. I've tried to read the Queios piece, but think I need another couple of goes at it.

 

Well, it took me nearly twenty years to write!