I believe that consciousness-- your subjective experience has nothing to do with the brain, but that everything we attribute to being human is because of the brain's functions intertwined with your subjective experience 'piloting' your body.
Imagine for example: You have a drone that you can control with a controller. However, the controller is the only way you can get data back from the drone. So obviously when the controller is fucked with, damaged, impaired, or even modified or tampered with, your perception of what's happening to your drone will be radically altered.
The drone is your body, and the brain is the controller. If I had to guess to what extent your consciousness is and how much of your existence is your brain's function. I would guess that your subjective experience of being is your consciousness, and your ability to create new ideas from scratch is largely your consciousness. I maintain this view because the intuitive creation of an entirely new concept is mathematically impossible, barring random chance but it should be more than clear that technological innovation for us is far beyond just random chance. Indeed, we are also capable of understanding the underlying ideas behind something, unlike animals.
Personally I believe that animals are nothing more than biological machines, what you end up with when a brain operates on its own without a consciousness. I believe this because of the clear lack of behaviors that can't easily be explained away by simply functionalist explanations and comparisons to AI technology we've made, and complex behavior it's exhibited that some would attribute to requiring sapience to figure out. Really it lies in how much people personify things in the case of animals, and the low expectations people attribute just 'some fancy math' to being able to achieve, in AI.
Realistically it's pretty absurd to believe that your subjective being could possibly be generated by mere matter working on entirely deterministic physics. Bio-chemical or electrical. Especially when comparing our capabilities and behaviors to animals or computers. For instance: An animal has never once been recorded commiting suicide out of anguish or a mental state (The only comparable examples have clear machine-like behaviors to them, like sheep following their leader off a cliff like drones, or that one singular bridge in Japan, the only one in the whole world that dogs jump off of often and deliberately.)
Or, for another example: The mouse being hooked up to electrodes that stimulate their pleasure centers, which the mouse would repeatedly stimulate until they died of self neglect. You'd find similar results in an AI that you've modified to be able to give itself points contributing to whatever goal it is designed to achieve. It would neglect its intended real-world function in favor of just repeatedly giving itself points because that is what the AI is designed to strive for. Basically, you've broken it.
A human being in the same test would at the very least come to the conclusion that they still need to take care of themselves, even if only to prolong the amount of pleasure they feel. Hell, even much more realistically they may choose to savor the ability to stimulate that sensation and even refrain from using it, teasing themselves to enhance the experience of the sensation when they recieve it.
That's the funny thing about us, we can act counterintuitively to machines, imagine, and even put into practice novel ideas that we really just pulled out of our asses. Think about totally higher concepts with no actual basis in reality (like this very thread), and even through all of that convince ourselves that our own existence is nothing but some kind of an 'illusion', one that must be experienced by our own existence in order to be an illusion to begin with. It's utterly nuts and I love it.
Anyways, back to afterlife.
My belief is that because some things are possible, then everything is possible. Allow me to elaborate.
The rules of existence are clearly defined and unchanging, yet arbitrary in their methods. Gravity doesn't
have to work the way it does. Indeed, you could sit down right now and draft an alternative reality where gravity works differently but the entire system still functions properly under the new rules. You could even do huge things like cut out the entirety of quantum physics and leave only the more basic concepts (with modifications) and have a reality that apparently seems the exact same in terms of day-to-day life.
Which begs the question, why does reality exist the way it does, why is it so well defined, and why is it so well designed?
Now, what I mean by 'everything must be possible' is that in the absence of these rules of this reality, it must be possible to do anything. Absolutely anything, Because there is no rule to say you can't create limitlessly. Therefore, anything, absolutely anything is possible to create and experience.
After all, you are already capable of imagining anything. Even outside of anything remotely possible in this reality. You are capable of total creation in every way except material. One might argue that "I can't imagine anything! I can't imagine a color I've never seen before!" Correct, but also not.
You can conceptualize a color you've never seen before. And given the ability to, could make it, Though you do not have experience with that color, therefore you can't envision it. It's very easy to conceptualize anything, but you require experience to visualize, or properly imagine.
Try to imagine a 4 dimensional space. You can't. Now try to design a fourth dimension. It might take a little bit to get a foothold on the idea, but it's certainly possible to design a fourth dimension because we have made 4D engines we can run on computers.
Even more intriguing is that people were capable of learning how to navigate in and (given enough time) would be able to think in four dimensions.
That actually brings me to another neat thought, is that computers are capable of simulating absolutely anything. Except, they are (at least if I'm correct) incapable of simulating a subjectively conscious being, which means that in these computer simulated realities we are the only ones capable of properly populating them. It also opens up the question of if this ability to create simulated realities with the physical properties of electricity was also by design?
For example, any video game is its own reality. Instead of atoms and matter they use polygons, instead of dynamic physical movement they use spatial translation and an animation to create the illusion of movement. Not because 'it's just a video game' but because that's how it's built. You could make a game that works entirely off of dynamic physical interactions like real life, though it would be very hardware intensive. You could conceivably make an entire reality that exists the same way. Presumably controlled directly by your consciousness as oppose as by proxy via your body and into an input device.