"I cannot conceive of chimpanzees developing emotions, one for the other, comparable in any way to the tenderness, the protectiveness, tolerance, and spiritual exhilaration that are the hallmarks of human love in its truest and deepest sense."
Jane Goodall said that.
"I cannot conceive of humans developing the lung capacity and related physiological changes that would allow us to dive as deep and as long as sperm whales." I said that. Many species have particularly well-developed capacities that make them successful in some environmental niche. For humans, it's cognitive capacities.
The materialist view says thought is an epiphenomenon and what we think is the product of material processes in the brain, processes that are biochemically and genetically determined. Free will and rationality are an illusion. But why believe in reasoned thought if your every thought is foreordained by chemical interactions and responses to stimuli?
There are many different materialist positions. Your characterisation is a sweeping generalisation; in my experience, the majority of materialists think that thought is a subset of brain processes, a few think
consciousness is an epiphenomenon, many think free will exists (compatibilism) and the many more think rationality is the product of logical symbol manipulation in brain processes. A lot depends on the precise definitions of these terms, and there's a lot of talking at cross-purposes due to unstated but conflicting definitions.
It seems to me that a reasonable approach is to see things in term of levels of emergence or abstraction. Each level has its own descriptive language and concepts. For example, at one level, it's particles interacting - we use the language and concepts of physics to describe this level; at another level, it's chemicals interacting - we use the language and concepts of biochemistry here; at another level, it's cells interacting - we use the language and concepts of cell biology and neurobiology here; at another level, it's information processing - we use the language and concepts of information science here; at another level, it's behavioural - we use the language and concepts of anthropology here.
The level related to discussion of conscious experience straddles those of information processing and social behaviour - we use the language and concepts of the mind, thinking, experience, consciousness, etc., here.
Mixing levels of description is generally counterproductive, unless you're investigating how one layer is emergent from or interacts with another. So when talking about sub-atomic particles, it's pointless to talk of metabolism; and when talking about a living cell, it's pointless to discuss its sub-atomic particles. Similarly, when discussing thinking, consciousness, rationality, and behaviour, it's generally pointless to talk of chemical interactions (unless discussing the interactions of chemicals with these functions).
Mixing levels of description is a kind of category error. It makes no more sense to say that we can't think because we're just a bunch of chemicals, than it does to say that planes can't fly because they're just a bunch of metal and plastic pieces.
If an atheist tells you we are nothing but meat machines with no souls or free will, ask him on what basis he thinks he can say that. If his every thought is determined, not free, then there is no reason to think he has arrived at his viewpoint rationally. There is no reason to think he thinks.
This is the confusion that arises when mixing levels of description without good reason, and is often compounded by the use of poorly-defined concepts, open to multiple interpretations (such as 'free will', 'thinking', and 'rational').
Here are some more reasons to think we are more than our brains, that we exist both as individuals in some sense at one with our brains, but also in another sense independent of our brains.
So far, you haven't given
any reasons, just examples of confused thinking.
We can train our brains to rewire themselves. People with obsessive-compulsive disorder can be taught to think differently, and it
makes an actual difference in the physical wiring of the brain. Also people can be missing a large part of their brains and
still function normally!
This is not a problem for brain science. The basic mechanisms underlying brain plasticity, adaptation, learning, and redundancy, are being discovered in ever greater detail.
You might be interested in
Hebbian theory and its famous dictum, "Cells that fire together wire together". It was an early (and incomplete) description of how learning can occur in the brain by neurons increasing their connectivity. I was at a conference at the end of last year where film was shown of neurons,
in realtime and
in vivo, producing new and stronger synaptic connections under repeated stimulation, as part of a series of experiments showing the formation
and manipulation of memories.
With our brains we write music, dance the ballet, paint landscapes, play chess, and do theoretical physics. We send men to the moon and then bring them back. We contemplate our origin, what and who we are, and give thanks. Non-human primates don’t do these things. Furthermore, these abilities far exceed what is needed for survival, and at least in the case of theoretical physics and traveling to the moon, are not useful for finding true love. The verdict on chess is still out.
Extract from:
Ann Gauger
https://evolutionnews.org/2018/09/beyond-adapation-the-human-brain-is-something-new/
It's true that we've 'hit the jackpot' with the co-evolutionary synergies of our cognitive abilities, but this isn't magic; for example, abstraction and symbol manipulation in social contexts give rise to language and culture, which, in turn, produce selective pressure for further cognitive development, aided by cumulative knowledge.
So far, you've described is what we're particularly good at, but you haven't actually made an argument that this requires that we're 'more than just our brains', or 'independent of our brains' - unless it's an argument from incredulity, which, I'm sure you're aware, is a fallacy.