Philosophy Discussion Forums | A Humans-Only Club for Open-Minded Discussion & Debate

[Pattern-chaser]

If meaning is the criterion, we will never decide if anything is conscious. We create and assign meaning. We humans. Meaning is not an attribute of the universe, it's a sort of tag that we attach to things. It is not inherent or intrinsic to the things, it's all about us. So if you say meaning is the criterion, you are saying that we decide - or choose - who/what is conscious and who/what is not.

Meaning is always relative in the sense of being something for or to somebody; but there is a distinction between semantic meaning (the meaning of representations or signs, particularly linguistic ones) and nonsemantic meaning concerning ethical significance and importance (value, purpose) as in "the meaning of life".

Yes, but aren't both 'types' of meaning still created and assigned by humans? I think they are. So it remains our choice what is conscious and what is not. There is no fact or logic involved, not really.

[psyreporter]

(2019) Researchers: Yes, Plants Have Nervous Systems Too
“Faster than can be explained by diffusion” means that the transmission appears to be a meaningful signal rather than simply the normal course of diffusion in plants.
https://mindmatters.ai/2019/04/research ... stems-too/

No, plants do not have nervous systems! They are equipped with an electrochemical signaling system, and there are some analogies between such a system in a plant and a nervous system in an animal. However, the analogies are much too weak to justify the assertion that plants literally have nervous systems, because they are outweighed by relevant structural and functional differences. It is not the case that any old physiological signaling system or mechanism is a neurophysiological one!

Moreover, there is no justification for regarding the signal-information received and processed by plants as semantic information, because they lack the cognitive mechanisms required for a semantic interpretation of physical/chemical signals as meaningful signs.

The only thing that would be relevant is the 'meaning' of the denoted 'electrochemical signaling system'. When it is established that it serves a meaningful purpose (e.g. a physiological foundation for what can be denoted as 'consciousness'), one would not be able to make the assertion that it is invalid to refer to the system as being a nervous system.

The system contains many neurotransmitters that are also present in the human brain, including dopamine, norepinephrine, serotonin and histamine. Recent discoveries indicate that the root system of plants can grow many billions of cells at the tips of the roots that function in a similar way as brain neurons. For some plants, it would result in a number of neurons that rival those of the human brain.

Recently surprising similarities between plant cells and neurons
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2884105/

[Sy Borg]

Where we differ is the possibility of a grey area, proto-consciousness. My guess is that, for very simple life forms, consciousness is not continuous but occurs in flashes under certain conditions - moments of the very most rudimentary awareness that bridge the gap between what we call reflexes and what we think of as consciousness. This notion assumes that humanlike consciousness is vastly different to the most basic sense of being of simple organisms, virtually unrecognisable. The assumption here is that consciousness does not only differ as matters of degree or lucidity, but in basic structure and function.

I know I'm repeating myself, but (ontologically) there is no "possibility of a grey area", because phenomenal consciousness is an on-off affair, being either present or absent—no matter whether there are long continuous streams of experience or just discrete sequences of momentary "flashes" of experience.

There may be (and arguably are) huge differences—regarding the experiential/phenomenal content, the cognitive level ("lucidity"), and the spatiotemporal "form", order, or structure of consciousness—between human consciousness and the primitive consciousness of the first conscious species; but the conditio sine qua non of phenomenal consciousness is the presence of some experiential content or other.

QUOTE>
"…the three main dimensions of consciousness, their role in consciousness, their underlying neuronal mechanisms, and their alterations in corresponding disorders. The concept of content refers to the persons, objects and events in consciousness, the phenomenal contents as philosophers say. The contents are the main focus in the various neuroscientific suggestions for the neural correlates of consciousness (NCC). They imply stimulus-induced activity and are altered in patients with selective brain lesions. The concept of level refers to the different degrees of arousal and awakeness and thus to the state of consciousness. The level or state of consciousness is related to global metabolism and energy supply which are found to be impaired and highly reduced in disorders of consciousness like vegetative state and coma. Moreover, neural activity in brain stem and midbrain is supposed to play an essential role in maintaining arousal. This reflects what is described as “enabling conditions” or “neural prerequisites” of consciousness. The concept of form describes the spatiotemporal organization and structuring (“putting together”) of the contents in consciousness."

(Northoff, Georg. Unlocking the Brain, Vol. 2: Consciousness. Oxford: Oxford University Press, 2014. p. xlviii)
<QUOTE

Northoff is referring to humanlike consciousness. I think we have to forget almost everything about our kind of consciousness when considering what goes on with brainless and very small-brained life forms. For a long time the scientific establishment has consistently underestimated the consciousness of other life forms and never, ever overestimated. Why? Because we are using an outlier (human consciousness) as a yardstick. (It should also be said that we the impacts of brain injuries could be due to the brain being a broken "filter" rather than a broken "generator).

Most times, I will accept the odds laid out by scientific orthodoxy, but I think it significant that decades of laser focus on brains in consciousness studies, based on the assumption that brains are the sole producers of consciousness, have failed to address the "hard problem". The usual approach is to deny that the hard problem exists, which is reminiscent of the former assumption that there was nothing before cosmic inflation or the so-called singularity. Today it's accepted that that view was misguided and the mistake has been corrected, with renewed attempts to understand what triggered the state change referred to as the Big Bang.

So all these regulatory and filtering functions referred to by Georg Northoff are higher level responses. I think that separating the brain and studying it independently, and treating other body sysems as a black box, is just "chunking". Scientists isolate the brain to simplify an extremely complex field.

A brain-centric approach gives primacy to "the map" over "the territory". The brain is incomplete - nothing useful by itself - and I suspect that is why no progress on the hard problem has been achieved at all, even after decades and many millions of dollars put into detailed brain research. Brains only evolved to maintain metabolisms. With the evolution of brains, the distinction between these systems has dissolved as the two systems became ever more co-dependent and, perhaps, truly indivisible.

[Consul]

The only thing that would be relevant is the 'meaning' of the denoted 'electrochemical signaling system'. When it is established that it serves a meaningful purpose (e.g. a physiological foundation for what can be denoted as 'consciousness'), one would not be able to make the assertion that it is invalid to refer to the system as being a nervous system.

I've been talking about meaning in the semantic sense, not about meaning in the nonsemantic sense of purpose or function. To say that the signal-information used by plants isn't semantic information is to say that it lacks semantic properties (meaning, reference, truth/falsity) and thus doesn't represent anything. As it were, mere signal-information tells its receivers to do something by making them do it (in a nonsemantic causal way), but it doesn't tell them anything about reality.

The system contains many neurotransmitters that are also present in the human brain, including dopamine, norepinephrine, serotonin and histamine. Recent discoveries indicate that the root system of plants can grow many billions of cells at the tips of the roots that function in a similar way as brain neurons. For some plants, it would result in a number of neurons that rival those of the human brain.

Recently surprising similarities between plant cells and neurons
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2884105/

Whatever similarities there may be, there just is no discernible type of physiological system in plants which can literally and properly be called a nervous system.

"The past three years have witnessed the birth and propagation of a provocative idea in the plant sciences. Its proponents have suggested that higher plants have nerves, synapses, the equivalent of a brain localized somewhere in the roots, and an intelligence. The idea has attracted a number of adherents, to the extent that meetings have now been held in different host countries to address the topic, and an international society devoted to ‘plant neurobiology’ has been founded. We are concerned with the rationale behind this concept. We maintain that plant neurobiology does not add to our We begin by stating simply that there is no evidence for structures such as neurons, synapses or a brain in plants. The fact that the term ‘neuron’ is derived from a Greek word describing a ‘vegetable fiber’ is not a compelling argument to reclaim this term for plant biology.…"

Source: Plant neurobiology: no brain, no gain?

[psyreporter]

I've been talking about meaning in the semantic sense, not about meaning in the nonsemantic sense of purpose or function. To say that the signal-information used by plants isn't semantic information is to say that it lacks semantic properties (meaning, reference, truth/falsity) and thus doesn't represent anything. As it were, mere signal-information tells its receivers to do something by making them do it (in a nonsemantic causal way), but it doesn't tell them anything about reality.

According to professor Susanne Simard, trees communicate 'wisdom' (meaning). It seems logical that such is the case when advanced communication means (with several profound similarities of an animal nervous system) are present, and when considering that the term 'social creature' is applicable according to several professors.

Why would a plant exist by mere chemical reaction?

Random chance is not a logical explanation. If something would exist by accident, then it could also accidentally not exist, by which nothing would exist.

Whatever similarities there may be, there just is no discernible type of physiological system in plants which can literally and properly be called a nervous system.

It would be a question about official terminology, in which case you may be correct.

When the discovered system provides a basis for conscious experience, then the usage of the term as an analogy may be applicable.

[Consul]

There may be (and arguably are) huge differences—regarding the experiential/phenomenal content, the cognitive level ("lucidity"), and the spatiotemporal "form", order, or structure of consciousness—between human consciousness and the primitive consciousness of the first conscious species; but the conditio sine qua non of phenomenal consciousness is the presence of some experiential content or other.

QUOTE>
"…the three main dimensions of consciousness, their role in consciousness, their underlying neuronal mechanisms, and their alterations in corresponding disorders. The concept of content refers to the persons, objects and events in consciousness, the phenomenal contents as philosophers say. The contents are the main focus in the various neuroscientific suggestions for the neural correlates of consciousness (NCC). They imply stimulus-induced activity and are altered in patients with selective brain lesions. The concept of level refers to the different degrees of arousal and awakeness and thus to the state of consciousness. The level or state of consciousness is related to global metabolism and energy supply which are found to be impaired and highly reduced in disorders of consciousness like vegetative state and coma. Moreover, neural activity in brain stem and midbrain is supposed to play an essential role in maintaining arousal. This reflects what is described as “enabling conditions” or “neural prerequisites” of consciousness. The concept of form describes the spatiotemporal organization and structuring (“putting together”) of the contents in consciousness."

(Northoff, Georg. Unlocking the Brain, Vol. 2: Consciousness. Oxford: Oxford University Press, 2014. p. xlviii)
<QUOTE

Northoff is referring to humanlike consciousness. I think we have to forget almost everything about our kind of consciousness when considering what goes on with brainless and very small-brained life forms. For a long time the scientific establishment has consistently underestimated the consciousness of other life forms and never, ever overestimated. Why? Because we are using an outlier (human consciousness) as a yardstick. (It should also be said that we the impacts of brain injuries could be due to the brain being a broken "filter" rather than a broken "generator).

Yes, Northoff is referring to brain-based consciousness, and the human brain is his central object of study; but "the three main dimensions of consciousness" he's describing are part of its essence, no matter what kind of things its substrates are. Even the consciousness of a brainless immaterial soul would have those three dimensions.

Most animals have brains, so there is a lot of room for nonhuman minds (cognition and consciousness) in the animal kingdom.

Most times, I will accept the odds laid out by scientific orthodoxy, but I think it significant that decades of laser focus on brains in consciousness studies, based on the assumption that brains are the sole producers of consciousness, have failed to address the "hard problem". The usual approach is to deny that the hard problem exists, which is reminiscent of the former assumption that there was nothing before cosmic inflation or the so-called singularity. Today it's accepted that that view was misguided and the mistake has been corrected, with renewed attempts to understand what triggered the state change referred to as the Big Bang.

So all these regulatory and filtering functions referred to by Georg Northoff are higher level responses. I think that separating the brain and studying it independently, and treating other body sysems as a black box, is just "chunking". Scientists isolate the brain to simplify an extremely complex field.

A brain-centric approach gives primacy to "the map" over "the territory". The brain is incomplete - nothing useful by itself - and I suspect that is why no progress on the hard problem has been achieved at all, even after decades and many millions of dollars put into detailed brain research. Brains only evolved to maintain metabolisms. With the evolution of brains, the distinction between these systems has dissolved as the two systems became ever more co-dependent and, perhaps, truly indivisible.

The neuroscience of consciousness (NSC) hasn't "failed to address the 'hard problem'," since it's job is to solve this very problem. The scientists working in this field certainly don't deny that there is a tough nut to crack.
As for the question of explanatory progress in NSC, you mustn't forget that it's a comparatively new science, whose progress and success crucially depend on the progress of the technology of neuroimaging, without which detailed microscopic analyses of the extremely complicated structure and dynamics of neuronal networks are impossible.
Notwithstanding all the nontrivial epistemological, methodological, and theoretical problems NSC is confronted with, its basic working hypothesis—that natural consciousness is exclusively realized by and in animal brains—is not in jeopardy. The neuroscientists aren't idiots, because they are well aware that the brain qua organ of an organism is not itself a whole independent organism; but this fact doesn't refute their assumption that the brain is the one organ of consciousness in an organism.

[Pattern-chaser]

Most animals have brains, so there is a lot of room for nonhuman minds (cognition and consciousness) in the animal kingdom.

Yes indeed. But this topic concerns mainly plants. And if[/i] there is plant consciousness, it would surely differ radically from animal consciousness. It wouldn't be based in an animal brain, that much is clear. I think it is rash to try to constrain 'plant consciousness' at this stage in our knowledge, when we aren't even sure that plants can/could be conscious, never mind what form it might take.

[Consul]

Most animals have brains, so there is a lot of room for nonhuman minds (cognition and consciousness) in the animal kingdom.

Yes indeed. But this topic concerns mainly plants. And if there is plant consciousness, it would surely differ radically from animal consciousness.

In what (psychological) respects?

It wouldn't be based in an animal brain, that much is clear. I think it is rash to try to constrain 'plant consciousness' at this stage in our knowledge, when we aren't even sure that plants can/could be conscious, never mind what form it might take.

If plants were subjects of experience, they would arguably experience nothing more than a few kinds of sensations, and be incapable of emotion, imagination, and cogitation. They would also be incapable of introspection, of cognition or perception of their sensations.

[Consul]

If plants were subjects of experience,…[t]hey would also be incapable of introspection, of cognition or perception of their sensations.

According to higher-order theories of consciousness, totally uncognized or unperceived experiences are nonexperiences, because no state is a phenomenally conscious/experiential one unless its subject is aware of being in that state. Such an introspective awareness requires a highly developed cognitive mechanism that can hardly be implemented by the non-neuronal physiology of plants. So if the higher-order theory of consciousness is correct, plant consciousness becomes even more incredible than it already is from the perspective of the first-order theory of consciousness.

"Consciousness is the perception of what passes in a man's own mind."

(Locke, John. An Essay Concerning Human Understanding. 1690. 2:1;19.)

Note that this is a higher-order definition of "consciousness"! Given this definition, most animals lack consciousness, because they are incapable of introspective awareness of the contents of their consciousness.

[Sy Borg]

The neuroscientists aren't idiots, because they are well aware that the brain qua organ of an organism is not itself a whole independent organism; but this fact doesn't refute their assumption that the brain is the one organ of consciousness in an organism.

One does not need to be an idiot to have tunnel vision. Geniuses can have tunnel vision too. We are flawed humans.

The fact is that their assumption is only that - and the dynamics lead to a firming of convictions. That is, they become brain scientists because they are interested in consciousness and think that is the best area to study. Once, however, one is a brain scientist, it makes sense to sharpen one's focus further, to dig into so many unsolved details in, as you say, a relatively new field of research. Even so, all those millions of dollars, and all those brilliant minds put to the problem over decades - with zero results in terms of the hard problem. Neuroscientist findings have been of great use medically but not much philosophically. Fair enough too, since medical organisations are the ones paying their salaries.

But straight away, it is not correct to assigns exclusive functions to organs. That is just practical "shorthand", but not the reality.

Organs have specialities, but they perform other functions too. So digestive systems have many neurons and do a little of their own sensing, and brains do some of their own digesting, such as autophagy in neurons.

Autophagy is known to play an important role in synapse development as autophagy is induced in response to many developmental and environmental cues. Thus, autophagy may play an important role in the synapse growth and plasticity required for learning and memory.

So it makes no more sense to assume that the brain is the only possible generator of consciousness that it does to claim that the only digestion that ever occurs is in the gut.

[Pattern-chaser]

If plants were subjects of experience,…[t]hey would also be incapable of introspection, of cognition or perception of their sensations.

According to higher-order theories of consciousness, totally uncognized or unperceived experiences are nonexperiences...

...and these theories are compatible with plant consciousness (if there is such a thing), are they? If not, it seems a little rash to rely on them in such a search, wouldn't you say?

[Pattern-chaser]

If plants were subjects of experience,…[t]hey would also be incapable of introspection, of cognition or perception of their sensations.

According to higher-order theories of consciousness...

You write as though you have access to a definition and understanding of consciousness that is universal - mind-independent, and maybe lifeform-independent too? How else could you be so aware of the faculties that a conscious living thing must display?

As far as I am aware, we humans cannot even agree on a definition of the word/concept of consciousness, never mind an understanding of it. Philosophers and scientists alike are flailing around in the dark, hoping to come up with something useful and usable. And that's just the efforts that are aimed at human consciousness. If there is such a thing as plant consciousness, I think it would be worth starting our investigations from the position that we know nothing at all about this possibility, and proceeding from there. Do you agree?

[Consul]

You write as though you have access to a definition and understanding of consciousness that is universal - mind-independent, and maybe lifeform-independent too? How else could you be so aware of the faculties that a conscious living thing must display?

As far as I am aware, we humans cannot even agree on a definition of the word/concept of consciousness, never mind an understanding of it. Philosophers and scientists alike are flailing around in the dark, hoping to come up with something useful and usable. And that's just the efforts that are aimed at human consciousness. If there is such a thing as plant consciousness, I think it would be worth starting our investigations from the position that we know nothing at all about this possibility, and proceeding from there. Do you agree?

The question of the distribution of consciousness in nature presupposes a universal(ly applicable) concept of consciousness.

Sensations are the evolutionarily basic and original kind of subjective experiences; so plants would have to have some sensations at least in order to be (phenomenally) conscious. This is true no matter whether we adopt the first-order or the higher-order conception of consciousness.

Of course, the only (phenomenal) consciousness that is directly accessible to me is my own human one; so the meaning of my concept of consciousness is fixed with reference to (the contents of) my own human consciousness. However, it doesn't follow that my/our human concept of consciousness is applicable to human consciousness only. If that were the case, then we couldn't even meaningfully ask whether there are conscious nonhuman animals, plants, or inorganic things such as rocks.

QUOTE>
"The concept of phenomenal consciousness is given to us through our introspective first-person awareness of our own mental states. And it seems, then, that anything we are introspectively aware of (provided it has fine-grained nonconceptual content) is a definite instance of that concept. This is a claim that will prove important when turn to consider phenomenal consciousness in other species."
(p. 23)

"One important point that has emerged from our discussion is how difficult it is to find evidence that could dissociate phenomenal consciousness from reflective awareness and verbal report. This is a consequence of the first-person nature of the very concept of phenomenal consciousness. For possession of such a concept seems to constitutively depend on just such capacities. Yet most if not all nonhuman animals, of course, lack those capacities. All are incapable of verbal report; and most if not all are incapable of reflective higher-order thought about their own perceptual states. Somehow, then, we must find a way to project our first-person, introspectively grounded concept of consciousness into the minds of animals who may be incapable of forming or using such a concept. This is the basic challenge involved in ascribing phenomenal consciousness to animals. How can we get third-person evidence that would support the application of a first-person concept, except from cases where people can offer third-person evidence of deploying just the same sorts of first-person concepts as we do?"
(pp. 114-5)

(Carruthers, Peter. Human and Animal Minds: The Consciousness Questions Laid to Rest. New York: Oxford University Press, 2019.)
<QUOTE

By the way, the higher-order theorists do have a good point:

QUOTE>
"[H]ow do you distinguish an unaccessed state of phenomenal consciousness of which you are not aware from a nonconscious state of which you are not aware? Awareness in each case depends on access. So what is unaccessed phenomenal consciousness?"
(p. 164)

"First-order theorists have a difficult job—probably the most difficult job in the consciousness business. They have to explain how it is possible to have a conscious experience that you do not know you are experiencing."
(p. 174)

(LeDoux, Joseph. Anxious: Using the Brain to Understand and Treat Fear and Anxiety. New York: Viking, 2015.)
<QUOTE

By "unaccessed" he means "cognitively unaccessed" or "uncognized" ("unknown").

[Pattern-chaser]

You write as though you have access to a definition and understanding of consciousness that is universal - mind-independent, and maybe lifeform-independent too? How else could you be so aware of the faculties that a conscious living thing must display?

As far as I am aware, we humans cannot even agree on a definition of the word/concept of consciousness, never mind an understanding of it. Philosophers and scientists alike are flailing around in the dark, hoping to come up with something useful and usable. And that's just the efforts that are aimed at human consciousness. If there is such a thing as plant consciousness, I think it would be worth starting our investigations from the position that we know nothing at all about this possibility, and proceeding from there. Do you agree?

The question of the distribution of consciousness in nature presupposes a universal(ly applicable) concept of consciousness.

Good, we agree on this at least. So I think we should set the former aside for now, and concentrate first on the latter: "a universal(ly applicable) concept of consciousness".

Sensations are the evolutionarily basic and original kind of subjective experiences; so plants would have to have...

You're doing it again. You are pursuing plant consciousness without having laid out the knowledge and understanding that we both agree is needed before we start: "a universal(ly applicable) concept of consciousness". Without this we cannot know what plants "would have to have", can we?

[Pattern-chaser]

Of course, the only (phenomenal) consciousness that is directly accessible to me is my own human one; so the meaning of my concept of consciousness is fixed with reference to (the contents of) my own human consciousness.

Therefore, you cannot - i.e. are not able to - carry out a formal scientific or philosophical investigation into plant consciousness, can you? So what do you propose? Should we abandon this quest, or is there a way we can proceed?