We don't know everything for sure. And we'll never know everything. But, we know enough up and down the physical stack through biology, chemistry and physics that there isn't some non-physical other going on in there.
Here's where the idea of life after death really breaks down for me: If you have a degenerative disease when do you get to this afterlife? Some people have effectively died long before they die, in terms of mind. If you see this as a process that is entirely physical it makes sense, it's sad but it makes sense. If you think there's something non-physical there then it poses some really hard questions: did they die already? why do personality changes happen if who a person is is contained in some non-physical thing? when they do die does the degenerated form go to the afterlife or the whole, and if its the whole then what happened to the person that was degenerative? Now throw in non-human life where we have a continuum of brain complexity down to nothing and ask similar questions - it just makes no sense. Unless you hold humans above other animals, which I find really distasteful and short sighted. Really though, if you try to explain all this you're just explaining away needless complexity to justify wishing for something that seems very unlikely.
A christian chap I used to live with told me that after we die our soul goes to heaven but its just our consciousness and not our personality, and we spend the rest of all time praising god. Well, not me, I was going to hell for not believing. Honestly, of the things he described, not sure which sounded better, but a materialistic death definitely trumps either of those options.
Here's where the idea of life after death really breaks down for me: If you have a degenerative disease when do you get to this afterlife? Some people have effectively died long before they die, in terms of mind. If you see this as a process that is entirely physical it makes sense, it's sad but it makes sense. If you think there's something non-physical there then it poses some really hard questions: did they die already? why do personality changes happen if who a person is is contained in some non-physical thing? when they do die does the degenerated form go to the afterlife or the whole, and if its the whole then what happened to the person that was degenerative? Now throw in non-human life where we have a continuum of brain complexity down to nothing and ask similar questions - it just makes no sense. Unless you hold humans above other animals, which I find really distasteful and short sighted. Really though, if you try to explain all this you're just explaining away needless complexity to justify wishing for something that seems very unlikely.
A christian chap I used to live with told me that after we die our soul goes to heaven but its just our consciousness and not our personality, and we spend the rest of all time praising god. Well, not me, I was going to hell for not believing. Honestly, of the things he described, not sure which sounded better, but a materialistic death definitely trumps either of those options.