Like I said, it is a thought exercise. What's wrong with the thought that "life" begins with bonding with the mother? Without that, the fertilized egg will die 100% of the time. Is that really life?
-PJ
Because it is an inherently flawed thought experiment.
1. Would it be equally valid to posit that "life" begins when the newborn "first opens its eyes?" There are, after all, numerous mentions in the Bible and other "traditional Christian texts" to "first seeing the light of the world." Anything "wrong" with that? Why?
Without that, the fertilized egg will die 100% of the time. Is that really life?
2. Okay, so how about defining the "beginning of life" with the first breath the newborn takes? After all, without that, the newborn will die 100% of the time.
"Attachment," as you call it, is a purely arbitrary point in time! There is nothing "magical" or "special" about it!
You can see that when you substitute various other points in time. It then becomes apparent that they are all arbitrary!
From a merely human point of view, seeing a child open its eyes, suck at its mother's breast, etc. are confirmations that it is, indeed, alive. But that is merely because our meagre human senses and sensibilities are limited.
Regards,