Does psychoactivity reveal the mind's physical basis?

1. What is the mind’s physical basis? We know the answer since a long time:

   The mind’s physical basis is the brain.

   But that’s not the real issue. The real problem is:

   How does the mind work?

2. One may use as a working definition:

   The mind are the mental processes of the brain.

   These processes constitute the human data processing to construct information. This information controls how the person behaves and acts as an agent.

3. The details are researched by neuroscience and cognitive psychology - but not by musing about metaphors from Heraclitus or about etymology like Heidegger did.

4. Added in reply to a comment: The subjective method of observing the mind at work is introspection. One may introspect those mental processes which are conscious.

How close can the nature of mind be brought to its chemical reactive component?

This question is partially tendentious if it makes the presumption that the chemistry in our central nervous system is purely "reactive". Effects are caused by previous effects, but become active causes for further effects.

To answer the question, with both phenomenology (the experiential side) and biological process in mind, I believe we should first of all consider physical pain (and various ways to block pain). Next, we should consider emotions such as wonder or surprise, i.e. an emotion that is not a full emotion, but rather a pre-emotional state signalling a violation of expectations of which the subject only becomes aware by feeling surprised. Pain is the most basic emotion (and in a way the most elusive one). Surprise is the start of consciousness.

The philosophical question is why do I feel pain, i.e. feel it as "my" pain?^A The only answer to that is (similar to the one given in Buddhism) that there is no conceptual distinction here: "me" and "my pain" define eachother. Pain is that which, at the most basic level, subjectivizes me, it defines the boundaries of the (bodily) "self". Functionally it is a demand for self-preservation.

(A) We actually don't just feel pain as purely "my" pain. It's impossible, unless you've numbed yourself, not to feel some pain when you see another creature in pain, especially one of your own species or one that is more similar to you. Spinoza already noted this in Ethics, III, prop. XXVII:

PROP. XXVII. By the very fact that we conceive a thing, which is like ourselves, and which we have not regarded with any emotion, to be affected with any emotion, we are ourselves affected with a like emotion (affectus).

From which he derived as one corollary:

We seek to free from misery, as far as we can, a thing which we pity.

And we know that this has a neurological basis in the Mirror Neuron System. (The formal equivalent in a mathematical model would, I think, be a fixed point.)

Brain damage of specific types is probably a better, clearer example of the physical basis of mind. But you have to be clear what the issue is.

For Greeks their word for spirit meant breath, pneuma like in pneumatic. Interrupting the breath leads to death. The dependency of the mind on the continued intactness of the body, has always been clear.

But then, there is a widespread intuition that we 'decide who to be' on a mental level, with regard only to our thoughts, uninfluenced by the body. This occurs against a wider discourse of animals and humans that are more like animals being ruled by their bodies, but the wise, the philosopher, has attained some higher faculties that free them from the impulses of the body. This is obviously nonsense, but pervasive. In Idealist and Dualist philosophies this kind of intuition has been formalised, with the mental realm being 'more real', or causally supervenient on the physical while itself causally independent on it.

Mind-altering substances I would suggest don't show the physical-material dependence of the mind on the body, more than patterns of symptoms that go with very specific brain damage do. But, they do help show mental systems at work, like optical illusions help us understand visual perception.

psychedelic

suggested by British-born Canadian psychiatrist Humphry Osmond in a letter to Aldous Huxley and used by Osmond in a scientific paper published the next year; from Greek psykhē "mind" (see psyche) + dēloun "make visible, reveal" (from dēlos "visible, clear," from PIE root *dyeu- "to shine").

-from Etymonline

A common effect of psychedelic substances is to open up greater pattern recognition, including pareidolia in the visual field, but also feelings of noetic revelation about connections between ideas. DMT is particularly interesting as it is endogenous, it is found naturally in the brain, at higher rates during birth, and associated with near-death and panic situations where time is experienced as slowing down. The commonality between psychedelics seems to be inducing neuroplasticity, and with DMT we can see a biologically functional role for this. The cortical regions typically responsible for self-referential processing that we call the default-mode network lose their organizing control, and this seems to go not just with heightened pattern recognition, but an openness to literally rewiring aspects of the brain like our orientation around what is felt to be valuable or meaningful.

The prospects for psychedelic assisted therapies are fascinating, not so much for revealing that chemicals and physical conditions affect the brain, which in science should be a given. But more for helping us understand how our habits shape perceptions and mental activity, by opening people up to changing their mental habits.

I personally find the OrchOR hypothesis very interesting, with the idea microtubules involve quantum behaviour in mental activity, memory, and connectedness across the brain. Specific substances have some distinct areas of influence, like say ibogaine seems to interact strongly with dopamine-associated reward activities. But I would look for the commonality in impact between these very different chemical molecules, to their impact on microtubules like for instance in explaining the incredibly low dose threshold for LSD.

The paper LSD Modulates Proteins Involved in Cell Proteostasis, Energy Metabolism and Neuroplasticity in Human Brain Organoids indicates there is link between LSD effects and microtubule-associated protein 2, which colocates with serotonin in dendrite growth cones, and functions to stabilize neuronal shape by promoting microtubule synthesis and cross-linking with other components of the cytoskeleton. So I'd say this is at least plausible.

There is overwhelming experimental evidence that mental activities are highly correlated with electrochemical effects in the brain. I won't try to summarise it, as there is a ton of information readily available online. However, the remaining explanatory gap is still the classic one of how do our feelings, experience and self awareness arise from it all. Even if we nail down the correlation to the nth degree, saying such and such brain activity always coexists with feeling bored, say, that still won't explain what it's like to feel bored.

You ask:

Does psychoactivity reveal the mind's physical basis?

No more or less than neural correlates of consciousness more broadly. Depending on how one defines mind, which is arguably an essentially contested concept, the mind is often taken to be an abstraction that correlates with concrete operations of the brain. When a person proposes a proposition about how the mind relates to the brain, that person is proposing the rudiments of a theory of a philosophy of mind. Trying to reduce that correlation to causation has been a source of much zealous debate for thousands of years.

This gives the philosopher of mind many sorts of responses as the taxonomy of theories recognizes based on the categories (SEP) one recognizes as fundamental: monism, dualism, and pluralism. From here, does one say emergence plays a role? Supervenience? Are categories in some sense parallel? Can we specifically identify one event type with another in the distinct categories? Have we simply decided to eliminate or reduce categories? The responses surely have a permutational flavor.

If by psychoactivity, you mean the effects of psychoactive compounds, then such activity supports the metaphysical claim that the mind is psychological in nature and that the best way to do philosophy of mind is with a naturalized epistemology. This is actually one of the hallmark claims of early analytical philosophy which began to take the phenomenalism of the early 19th century and turn that on its head advocating physicalism in its place. Starting with Wundt, the first self-proclaimed psychologist, physical science earnestly began presuming that the brain and body are responsible for mind, and exploring what science has to say about that presumption.

Today, one can appeal to psychology, philosophy of psychology, neuroscience, cognitive science, and particularly cognitive neuroscience in particular when discussing the mind. In that sense, psychoactivity is just another bolt in the quarrel for producing useful operational definitions of abstract structures and events of the mind. In my own interests in computer science, this has led to simulations of the mind under the heading cognitive architecture. From WP:

Cognitive neuroscience is the scientific field that is concerned with the study of the biological processes and aspects that underlie cognition,1 with a specific focus on the neural connections in the brain which are involved in mental processes.2 It addresses the questions of how cognitive activities are affected or controlled by neural circuits in the brain.

See also:

• Psychological Explanation by Jerry A. Fodor
• Neuroscience & Philosophy: Brain, Mind & Language by Bennett, Dennett, et al.
• Cognitive Neurosciece by Richard Passingham
• Philosophy of Mind by John Heil
• Cognitive Science, 3rd Ed. by Jose Luis Bermudez