[Heartlander]

Question: What is the difference, besides the fact that one is breathing, between a dead atheist and a live atheist?

[Dimensio]

Question: What is the difference, besides the fact that one is breathing, between a dead atheist and a live atheist?

All cell function, brain activity, oxygen intake (with respective conversion to CO2 -- this doesn't count for any bacteria in either specimen's body), usually body temperature as well.

Lots of differences, those are just a few. Actually, the being an atheist has little to do with most of the differences.