system
Given the following post, respond as if you're commenting on Reddit:
human
CMV: There is so little evidence to support/explain how an afterlife could be possible that believing in it is foolish.

Given everything we understand about consciousness, it seems pretty clear that the brain is required for any kind of conscious experience, and that once a brain that is not functioning, or has rotted away all together, there will be no other consciousness to speak off.

We already know that certain parts of the brain are responsible for certain functions, such as the  cerebrum. If we were to cut out the cerebrum, we would either destroy the patient's ability to think, or we would destroy their consciousness.

Alternatively, if we were to remove the parts of the brain that interprets our senses, then we would lose those senses (sight, smell, etc). So we all agree that without the brain those senses evaporate, why would our consciousness, our being, or our person-hood be any different? Because if you have no sensation, no thinking, no mental/physical activity, what is the difference between that and someone who is 'gone?'

We agree that those who have not yet been born do not exist because they have none of the above criteria (thoughts, sensations). What possible reason is there to think those who have died are in any different kind of state?

So to sum up: Due to our understandings of the brain, the belief in the afterlife can be dismissed as a childish fancy borne our of fear and grief. It is just as baseless, perhaps even more so, than believing any of the following: That skin colors make certain people superior/inferior, that vaccines cause autism, that the earth is flat, that your astrological sign determines your personality, that Lord of the Rings is historical fact, or that Elvis is alive.

Granted due to the existential nightmare we find ourselves in the belief in an afterlife, while being even more unfounded and irrational than any of the above, is much, much more forgivable and understandable, due to the above mentioned fear and anxiety.

If I'm wrong let me know. I'd love to have reasons to stop believing that we're all destined for the void.

Edit: A few people have made the argument 'But belief in the afterlife helps people act better/be happy, or in other ways make their lives better.'

True, but good effects say nothing about the truth values of their claims. Hence, I will not accept this answer.

Further edit: This has produced a heck of lot of responses. Thank you all for your input, but know that I might not respond to you all.
gpt
Being the devil's advocate here but I'd like to point out that the afterlife and religion is something fundamentally beyond science. All of your other examples can theoretically be proven or disproven, but the spiritual afterlife is a hypothesis that can't be tested. If science can't make any significant theories about it, then it's pretty much anyone's guess and believing or not believing is irrelevant. Is it really much more foolish than believing in a multiverse theory or any other hypothesis that can't be tested?