(February 14, 2012 at 2:53 pm)DeistPaladin Wrote: Sentience is the "I" that we mean when we say "I am". It is the state of being self-aware of one's own existence. It is the ability to experience reality.
We have moral obligations toward other sentient beings. We empathize with their feelings of pain and fear. We identify with their yearning for rights and liberty. We are evolved as social animals and a secular understanding of morality typically hinges on that sense of connection and desire for social justice.
We have no moral obligations toward things that do not think, do not feel and do not have any capacity for self-awareness. You can't torture a rock. You can't murder a chair. These are things which don't feel pain, fear or any other kind of experience.
A single-cell organism is a thing. It has no brain by which to experience reality or operate on any basis other than automated stimulus-response. We think nothing of taking anti-biotics and thereby cause a holocaust of microscopic beings. Nor should we.
At conception, the zygote is a thing. It is no more a sentient being than an amoeba. Significant brain development, on the scale needed for sentience, doesn't occur until week 21, well after the 1st trimester. It is only after this point that the developing fetus begins to respond to outside stimulus.
I'm speaking as one who used to be "pro-life". My argument then was "person A's right to life trumps person B's right to choice". When I studied fetal development, I realized there was no "person A" and so the entire foundation of my beliefs was gone. I've been "pro-choice" ever since.
I agree with your argument in principle, but have some quibbles about the phrases. First of all, I believe the correct definition of sentience is simply awareness of the surroundings. Awareness of an entity such as "I" is not required. The more correct phrase would be self-awareness.
Secondly, why would something create a moral obligation on us simply by being self-aware? Your premise, that it is based on empathy, falls short if one feels no empathy towards the subject. If it is shown that a murderer does not feel empathy towards the victim, then does it follow that he has no moral obligation towards him?