This is quite possibly the most complete and defined explanation of both the debate, and the logic...literally changed my understanding.
Here is a small snippet, but reading the whole article is worth the time.
"
Every one of us began from a dot. A fertilized egg is roughly the size of the period at the end of this sentence. The momentous meeting of sperm and egg generally occurs in one of the two fallopian tubes. One cell becomes two, two become four, and so on—an exponentiation of base-2 arithmetic. By the tenth day the fertilized egg has become a kind of hollow sphere wandering off to another realm: the womb. It destroys tissue in its path. It sucks blood from capillaries. It bathes itself in maternal blood, from which it extracts oxygen and nutrients. It establishes itself as a kind of parasite on the walls of the uterus.
So, if only a person can be murdered, when does the fetus attain personhood? When its face becomes distinctly human, near the end of the first trimester? When the fetus becomes responsive to stimuli--again, at the end of the first trimester? When it becomes active enough to be felt as quickening, typically in the middle of the second trimester? When the lungs have reached a stage of development sufficient that the fetus might, just conceivably, be able to breathe on its own in the outside air?
The trouble with these particular developmental milestones is not just that they're arbitrary. More troubling is the fact that none of them involves uniquely human characteristics--apart from the superficial matter of facial appearance. All animals respond to stimuli and move of their own volition. Large numbers are able to breathe. But that doesn't stop us from slaughtering them by the billions. Reflexes and motion are not what make us human.
Other animals have advantages over us--in speed, strength, endurance, climbing or burrowing skills, camouflage, sight or smell or hearing, mastery of the air or water. Our one great advantage, the secret of our success, is thought--characteristically human thought. We are able to think things through, imagine events yet to occur, figure things out. That's how we invented agriculture and civilization. Thought is our blessing and our curse, and it makes us who we are.
Thinking occurs, of course, in the brain--principally in the top layers of the convoluted "gray matter" called the cerebral cortex. The roughly 100 billion neurons in the brain constitute the material basis of thought. The neurons are connected to each other, and their linkups play a major role in what we experience as thinking. But large-scale linking up of neurons doesn't begin until the 24th to 27th week of pregnancy--the sixth month.
By placing harmless electrodes on a subject's head, scientists can measure the electrical activity produced by the network of neurons inside the skull. Different kinds of mental activity show different kinds of brain waves. But brain waves with regular patterns typical of adult human brains do not appear in the fetus until about the 30th week of pregnancy--near the beginning of the third trimester. Fetuses younger than this--however alive and active they may be--lack the necessary brain architecture. They cannot yet think.
Acquiescing in the killing of any living creature, especially one that might later become a baby, is troublesome and painful. But we've rejected the extremes of "always" and "never," and this puts us--like it or not--on the slippery slope. If we are forced to choose a developmental criterion, then this is where we draw the line: when the beginning of characteristically human thinking becomes barely possible.
It is, in fact, a very conservative definition: Regular brain waves are rarely found in fetuses. More research would help… If we wanted to make the criterion still more stringent, to allow for occasional precocious fetal brain development, we might draw the line at six months. This, it so happens, is where the Supreme Court drew it in 1973--although for completely different reasons.
Its decision in the case of Roe v. Wade changed American law on abortion. It permits abortion at the request of the woman without restriction in the first trimester and, with some restrictions intended to protect her health, in the second trimester. It allows states to forbid abortion in the third trimester, except when there's a serious threat to the life or health of the woman. In the 1989 Webster decision, the Supreme Court declined explicitly to overturn Roe v. Wade but in effect invited the 50 state legislatures to decide for themselves."
http://2think.org/abortion.shtml
Hope you find it a good read.
Here is a small snippet, but reading the whole article is worth the time.
"
Every one of us began from a dot. A fertilized egg is roughly the size of the period at the end of this sentence. The momentous meeting of sperm and egg generally occurs in one of the two fallopian tubes. One cell becomes two, two become four, and so on—an exponentiation of base-2 arithmetic. By the tenth day the fertilized egg has become a kind of hollow sphere wandering off to another realm: the womb. It destroys tissue in its path. It sucks blood from capillaries. It bathes itself in maternal blood, from which it extracts oxygen and nutrients. It establishes itself as a kind of parasite on the walls of the uterus.
So, if only a person can be murdered, when does the fetus attain personhood? When its face becomes distinctly human, near the end of the first trimester? When the fetus becomes responsive to stimuli--again, at the end of the first trimester? When it becomes active enough to be felt as quickening, typically in the middle of the second trimester? When the lungs have reached a stage of development sufficient that the fetus might, just conceivably, be able to breathe on its own in the outside air?
The trouble with these particular developmental milestones is not just that they're arbitrary. More troubling is the fact that none of them involves uniquely human characteristics--apart from the superficial matter of facial appearance. All animals respond to stimuli and move of their own volition. Large numbers are able to breathe. But that doesn't stop us from slaughtering them by the billions. Reflexes and motion are not what make us human.
Other animals have advantages over us--in speed, strength, endurance, climbing or burrowing skills, camouflage, sight or smell or hearing, mastery of the air or water. Our one great advantage, the secret of our success, is thought--characteristically human thought. We are able to think things through, imagine events yet to occur, figure things out. That's how we invented agriculture and civilization. Thought is our blessing and our curse, and it makes us who we are.
Thinking occurs, of course, in the brain--principally in the top layers of the convoluted "gray matter" called the cerebral cortex. The roughly 100 billion neurons in the brain constitute the material basis of thought. The neurons are connected to each other, and their linkups play a major role in what we experience as thinking. But large-scale linking up of neurons doesn't begin until the 24th to 27th week of pregnancy--the sixth month.
By placing harmless electrodes on a subject's head, scientists can measure the electrical activity produced by the network of neurons inside the skull. Different kinds of mental activity show different kinds of brain waves. But brain waves with regular patterns typical of adult human brains do not appear in the fetus until about the 30th week of pregnancy--near the beginning of the third trimester. Fetuses younger than this--however alive and active they may be--lack the necessary brain architecture. They cannot yet think.
Acquiescing in the killing of any living creature, especially one that might later become a baby, is troublesome and painful. But we've rejected the extremes of "always" and "never," and this puts us--like it or not--on the slippery slope. If we are forced to choose a developmental criterion, then this is where we draw the line: when the beginning of characteristically human thinking becomes barely possible.
It is, in fact, a very conservative definition: Regular brain waves are rarely found in fetuses. More research would help… If we wanted to make the criterion still more stringent, to allow for occasional precocious fetal brain development, we might draw the line at six months. This, it so happens, is where the Supreme Court drew it in 1973--although for completely different reasons.
Its decision in the case of Roe v. Wade changed American law on abortion. It permits abortion at the request of the woman without restriction in the first trimester and, with some restrictions intended to protect her health, in the second trimester. It allows states to forbid abortion in the third trimester, except when there's a serious threat to the life or health of the woman. In the 1989 Webster decision, the Supreme Court declined explicitly to overturn Roe v. Wade but in effect invited the 50 state legislatures to decide for themselves."
http://2think.org/abortion.shtml
Hope you find it a good read.