When Does Life Begin and When Does It End?

[tecoyah]

Pertinent to the discussion....and likely the best evaluation of this topic I have ever seen.

Well worth the read for those interested....but this is the part important to this conversation:

"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."

The abortion debate - Carl Sagan

 

[Enginerdy]

What I am pointing out is that the potential of the embryo and the person in the coma for attaining human consciousness are in fact not the same.

The comatose person, having already attained human consciousness previously, already has developed biological stuff for human consciousness and also other stuff in the brain based on that human consciousness, just as the person who has learned the second language has a brain with second language biological and other stuff in it.

Just because the comatose person can't access human consciousness at the moment does not mean that the brain as it exists is not made of the human consciousness biology and other stuff of human consciousness already attained. This is like the second language person who cannot access the second language right now but still has a brain partly made of the second language biological and other stuff already attained.

When the comatose person gains consciousness, it is a sudden or immediate return to being conscious. All the stuff that the brain had biologically and all the stuff human consciousness previously put into the brain is there. The comatose person doesn't have to develop any unprecedented, new biological stuff to be conscious. But the embryo has to develop unprecedented, new biological stuff just to have human consciousness, and it can only do that slowly.

In all cases, the person in the coma already has a fully human brain capable of human consciousness and there is objective empirical evidence right in the brain that human consciousness has operated there. But the embryo has not yet developed fully a human brain capable of human consciousness, so there is no objective empirical evidence of that kind. If we examine and compare these brains, it is true that neither one is exhibiting behavior associated with human consciousness, but it is also true that one exhibits evidence caused by capability of human consciousness and evidence of human consciousness having operated there. That makes the two brains different.

Understood, and iangb was the first to point this out.

I acknowledged he had a good point and modified the scenario to include a baby born in a coma, since consciousness may not be achieved until a baby is about 5 months old.

 

[Enginerdy]

Life is a continuum.
Life started when the first paramecium crawled through the primal ooze billions of years ago.
Life will no doubt end with some cataclysmic astral-geological event.
I realize that's not the answer you were looking for ,but you need to phrase the question in a more relevant way.
Sperm and ova are, without doubt, living cells, but neither one is capable of consciousness. So obviously life and consciousness are nowhere near the same thing.
As to my opinion on the punctuation of consciousness. Neither are events...they are processes.
You are trying, it seems, to assign event status to processes and that leaves you chasing your tail like millions have before you, trying to simplify an answer to a complex conundrum.
For legal reasons, of course, event status needs to be assigned to the punctuation of life ...usually these event assignments have been made by non-science people and have always seemed unrealistic, unsatisfactory and somewhat arbitrary.
Zygote,ten weeks, conception, viable, brain dead, flat-line etc ...

Actually, I did expect that answer since I messed up the title of the thread. My questions from the OP are regarding a human life, not life in general. My fault for messing up the title.

 

[Enginerdy]

That's a poor way to do it.

I've been known to do things poorly before.

 

[Enginerdy]

I wasn't talking about conciousness and awareness, I was talking about experiencing a sensation - mostly because there are all sorts of thought experiments which show it is very hard to accurately measure 'awareness', but 'sensation' is a bit easier (EEG scans and the structure of the brain itself). It's playing it safe.

Well, that is my point in this thread, it is about consciousness. The scenario and comparison were always about consciousness. That consciousness is too difficult to determine as the point at which a human life begins. If it is more about sensation, or the beginning of brain activity, that’s different. Still, that time period varies just as viability varies somewhat.

Before you seemed to focus on “potential” and “actual” and you referenced including the “potential” of a sperm cell.

Going back to the comparison in the OP that the chance a zygote has to gain consciousness is significantly greater than the chance one sperm cell has just among one ejaculate, let alone considering whether an ovum is ready at the time.

For me, that single change from sperm to zygote is a significant enough change in potential to gain consciousness (or develop brain activity or sensation) to indicate conception is an important starting point to a human life, not just from a biological point of view, but perhaps also from a philosophical one.

I would say (as implied in my original post, though I never made it clear) that I would say the 'human life' starts at viability. The person starts at first sensation, and develops as the brain continues to grow and mature.

Thanks for clarifying your position.

 

[Enginerdy]

Pertinent to the discussion....and likely the best evaluation of this topic I have ever seen.

Well worth the read for those interested....but this is the part important to this conversation:

"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."

The abortion debate - Carl Sagan

Big fan of Sagan, thanks for posting this.

 

[choiceone]

Wow very interesting! You obviously know way more than I do but a lot of people do. I'm wondering what the percentage would remain viable once implanted without any outside interference. That doesn't in any way diminish the wonderful well thought out response you made. You go girl!

Thank you for your compliment. I think minnie knows what you wonder about, because she has posted before on estimated percentages of zygotes/blastocysts that don't implant and percentages of known pregnancies that end in miscarriage - though some unknown pregnancies would end in miscarriage, too, without the woman being aware of it.

 

[choiceone]

Sperm cells need time to develop and mature and they are also, without any doubt ,very much alive.
Why start at zygote?

When we address the anti-choice perspective, anti-choicers point out that oocytes and sperm separately do not have DNA that allow them to develop naturally all the way into born children, but zygotes have such DNA. So my point is that, despite the DNA, zygotes still can't develop thus without using the woman's body. Abortion of a pregnancy means ending that use.

 

[sneakosview]

Thank you for your compliment. I think minnie knows what you wonder about, because she has posted before on estimated percentages of zygotes/blastocysts that don't implant and percentages of known pregnancies that end in miscarriage - though some unknown pregnancies would end in miscarriage, too, without the woman being aware of it.

Very nice!

 

[1750Texan]

Life begins when the human brain begins to function, and ends when it ceases to function.

the fuction of the Human brain is to control all systems and fuctions of the human body. Since the pre-natal brain is not fully in control of all those autonomus fuctions...Then Human life begins as the brain takes over all functions.

 

[Enginerdy]

the fuction of the Human brain is to control all systems and fuctions of the human body. Since the pre-natal brain is not fully in control of all those autonomus fuctions...Then Human life begins as the brain takes over all functions.

At what point during development does the human brain control all systems and functions of the human body?

 

[haymarket]

Life begins when the kids are old enough to move out of the house.

 

[Removable Mind]

At what point during development does the human brain control all systems and functions of the human body?

I think the question might be more akin to: At what point can a fetus can continue to develop and thrive outside of the womb,

I say that because premature births happen. And while it's unlikely that brain of a premature is fully developed, they are developed enough to control vital body functions outside of the womb.

Minnie, Choiceone, Year2Late, Lusra, Ocean, fairly frequently post information about fetal development and the age in which a fetus has the best chance of surviving outside womb.

I think about 21 weeks old is the youngest a fetus has been known to survive, but that's extremely rare. I think the average age of survival is somewhat older.

 

[minnie616]

I think the question might be more akin to: At what point can a fetus can continue to develop and thrive outside of the womb,

I say that because premature births happen. And while it's unlikely that brain of a premature is fully developed, they are developed enough to control vital body functions outside of the womb.

Minnie, Choiceone, Year2Late, Lusra, Ocean, fairly frequently post information about fetal development and the age in which a fetus has the best chance of surviving outside womb.

I think about 21 weeks old is the youngest a fetus has been known to survive, but that's extremely rare. I think the average age of survival is somewhat older.

Yes , the youngest premies to ever survive were 21 weeks 5 and 6 days.
They were considered to be medical miracles.

Expects agree it is highly unlikely any fetus younger than 21 weeks gestation will ever survive since their lungs and digestive systems are too underdeveloped even for the most advanced technology to help.

The limit of viability ( where 50 percent of premies survive even though major disabilities remain high ) is 24 weeks gestation.
It has remained at 24 weeks gestation for the last 12 years.

Most hospitals the USA do not offer neo natal units to a premie born before 23 weeks gestation.
They give the premie comfort care, keeping it warm and pain free until it expires naturally.

 

[Removable Mind]

Yes , the youngest premies to ever survive were 21 weeks 5 and 6 days.
They were considered to be medical miracles.

Expects agree it is highly unlikely any fetus younger than 21 weeks gestation will ever survive since their lungs and digestive systems are too underdeveloped even for the most advanced technology to help.

The limit of viability ( where 50 percent of premies survive even though major disabilities remain high ) is 24 weeks gestation.
It has remained at 24 weeks gestation for the last 12 years.

Most hospitals the USA do not offer neo natal units to a premie born before 23 weeks gestation.
They give the premie comfort care, keeping it warm and pain free until it expires naturally.

Thanks, Minnie. As you've pointed out above it seems brain development in terms of functionality is only part of the equation. Lungs and intestine development apparently don't out pace the development of the brain.

So the complexity of development is something like the old saying, "the sum of the parts are greater than the whole" applies to the surviveability of a prematurely born fetus.

 

[choiceone]

Fair enough. What if the scenario involved a baby born in a coma? Full consciousness and awareness might only be achieved as early as 5 months for babies.
When Do Babies Become Conscious? - Wired Science


Perhaps the scenario and comparison I provided doesn’t say anything about the philosophical start of a human life.

Either way, I’m just trying to get people who think consciousness is the start of a human life to think harder about that position.

This isn't just about mind and consciousness. The one case involves a body with only one head, with one brain, one nose, and one mouth: this body can be sustained by the breathing and intake of food of only one being, represented by that head and brain. The other case involves a body with two heads, each having one brain, one nose and one mouth: the body is sustained by the breathing and intake of food of each of the heads and therefore each of the beings. That would be true even if one twin went into a coma and the other didn't, because artificial life support available to any born person could be used for either or both of them. Neither lives parasitically on another biological being.

 

[choiceone]

At what point during development does the human brain control all systems and functions of the human body?

At birth. Before birth, the woman is providing many things to the fetus, so the fetus's body doesn't have to change and do various things that the born have to do. In the birth process and immediately afterward, the physiological systems and even the structure of its heart of the fetus/neonate change.

 

[1750Texan]

At what point during development does the human brain control all systems and functions of the human body?

during development...at no point.

 

[Enginerdy]

during development...at no point.

Perhaps not at a specific point, but is there a particular phase of development, a particular range of weeks? Is it before or after birth?

 

[Chocolate]

Minnies posts blew me away. Thank you so so much for sharing it really opened my eyes to this thread in many ways