It is our brains that make us humans unique. I'd turn to science to measure/determine 'thinking'. Every animal has a heart so that won't tell us anything.At what point do you think a fetus/child can "think?" How would you measure/determine that?
I think a detectable heartbeat would be a more precise measure of human development.
P.S. Your comparison to an already dying person in a coma is not apropos.
Please explain how a fetus before brain development is different from a person in a coma.
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