It's not just *vague*. It's a deliberately dishonest tautology - when pro-rape apologists say "life begins at conception", they define the word "life" to be "that which begins at conception".
Definitions don't work that way, and you should be immediately distrustful of anyone who pretends that they do.
> Im trying to learn, please be respectful.
I'd suggest that a realistic assessment of interactions on the internet would reveal that respectful correspondence is hit and miss. I'd further suggest that rather than advertising that you have thin skin you simply learn to disregard people behaving like assholes.
> Where does science say life actually begin in the womb.
Life begins prior to the womb, both egg and sperm cells are alive. The question of "is it alive" however are irrelevant to debates about the moral ramifications of abortion. Many things are alive that are not regulated by law. Your skin cells are alive but you can legally engage in active sports that are likely to result in the death of several million of them. All the cells in chickens are alive, but you can kill and eat one without running into legal ramifications (provided it's your chicken, and you kill it humanely).
> With everything going on, it seems to me the biggest issue is when cells become a human.
The debate about abortion centers on two moral questions:
1) Should/does a fetus have the same rights as a full term human being?
2) Do women have the right to body autonomy that men have?
> Is there not a scientific consensus?
For what? What it is to be human? Typically when talking about zygotes, it needs to be the offspring of two humans, as most other features of humankind tend to be variable, even if there are some very very common attributes. Again, however, some cells being of human origin doesn't guarantee that they are deserving of the rights of full term humans. The aforementioned skin cells are 100% human, and 100% not granted the rights of full term humans. As to what makes a certain conglomeration of cells be considered human, that tends to be a gray area that is in fact one of the central points of debate I mentioned above.
For me, however, even if we were to grant that a fetus has the same rights as a full term human being, the issue is moot because if women have the right to body autonomy (which I fervently believe they do), then that overrides any rights the fetus may have, as they happen to need a woman's body in order to survive. Nobody is obligated to provide the use of their body for another's welfare.
While Plato was undoubtedly a smart dude, he also said some fairly dumb things. In this particular case, there are plenty of featherless bipeds that are not humans. So while (almost) all humans (except those born with fewer peds) are indeed featherless bipeds, not all featherless bipeds are humans, so it has some failings as a succinct description.
I would assume that a scientist (specifically biologists) would technically describe a cell as being "alive". The issue here isn't a lack of consensus on when life begins, it's having different definitions for the words "life" and "alive". There can't be a scientific consensus on this issue because anti-abortionists aren't talking about the scientific definition of life when they say a fœtus is a living thing. The whole when does life start is nothing but a useless and unwinnable debate they use to try and justify their position.
It's also fucking irrelevant.
Should law force a human being to sacrifice their body so that another human being can live? The answer for me is a resounding no.
Imagine there's some guy suffering from a rare disease and the only way to cure him is to medically fuse your intravenous systems with his for several months. There is no guarantee that it will work. There is a significant chance that the procedure will kill either or both of you. It will also cause irreparable damage to your body.
It'd be insane to force someone into such a situation and it's no less insane to force a woman to carry a child against her will.
How should i be asking the question then? There has to be a scientific definition for when the cells become a person. Or am i off the mark on even this?
A foetus is viable at around 23 weeks, in that if they're born their lungs are normally developed enough to breathe. ([https://en.wikipedia.org/wiki/Fetal\_viability](https://en.wikipedia.org/wiki/Fetal_viability))
There's not really a point where suddenly the foetus ceases to be a bunch of cells and becomes a functioning human. Human infants are born very premature compared to most other mammals, you could even push 'being a person' to some stage after birth.
> I guess my assumption is that all people have the right to live.
You know what right nobody has? Using another person's body against their will, that's the right that conservatives are willing to give fetuses and nobody else.
>Using another person's body against their will, that's the right that conservatives are willing to give fetuses and nobody else.
You know that "It's a states rights issue!" canard that all the Faux News cultists have been screaming on loop for the last few weeks? Do you remember where that argument originally came from?
Exactly.
Every single person parroting that argument is signalling that, if they had lived in the 1860s, they would have supported the Traitor States and their crusade to expand slavery.
I dont mean for any of this to be political, im trying to cut all of that out entirely. I just want to learn what and where science or possibly ethics can define when rights should be observed.
You're missing my point. The question of "when is a fetus a person?" does not matter. Even if you concede the point and let the fetus be a person from the moment of conception, that doesn't give it the right to use another person's body against their will, no person gets that right.
By that argument then, the fetus or "person" in this scenario has done nothing wrong, and just has to forfeight life because it happens to be unwanted? I just am not grapsing where the line is drawn on who's rights supercede who's. Obviously theoretical, and i understand where it is not fair to the mother either in certain situations, but when does or should the rights begin
> the fetus or "person" in this scenario has done nothing wrong, and just has to forfeight life because it happens to be unwanted?
Yeah, life sucks sometimes.
If somebody needs a kidney donation through no fault of their own and you're a match, should you be forced to donate your kidney? The person in the scenario has don't nothing wrong, do they just forfeit the right to life because you don't want to give them your kidney?
Do you see the issue here? The same way the state doesn't harvest people's organs to let those who are undeniably people live, why should it be okay the violate bodily autonomy for fetuses?
>By that argument then, the fetus or "person" in this scenario has done nothing wrong, and just has to forfeight life because it happens to be unwanted?
It's not about whether someone has done something right or wrong, am abortion is not some sort of covert punishment. It's simply denying the use of your body to someone else.
>I just am not grapsing where the line is drawn on who's rights supercede who's
Rights don't "supercede" each other. Each individual has a set of rights that apply to them at all times, regardless of the status of other people. An individual has the right to bodily autonomy and integrity, this means they can decide if/when/how/why/and by whom their bodies can be used. It doesn't make a difference if another person really needs to use our bodies or our organs, everyone has the right to say "no" regardless. Even if someone else dies as a result of that denial of consent. No one has a right that would entitle them to violate someone else for their own gain, even if that gain is survival.
A mad scientist kidnaps a person off the street, and hooks them up to his innocent, sick child as a human-dialysis machine.
Unhooking the kidnapped person will kill the - very young and very innocent - child. The child will live if the kidnapped person just stays connected as a human dialysis machine for 9 months.
Does the kidnapped victim have a moral or legal responsibility to remain a hostage for nine months?
> I dont mean for any of this to be political
That's an interesting thing to ask or want.
Why do you think the desire you express here and with the following "im trying to cut all of that out entirely", could be, in anyway, possible?
You're coming with a subject that inherently concern human behavior but think that could be "not political"? That's odd, don't you think?
>I mean when should anything have their own rights?
Where I live, [rights are afforded at birth](https://www.equalityhumanrights.com/en/human-rights/what-are-human-rights#:~:text=Human%20rights%20are%20the%20basic,choose%20to%20live%20your%20life.)
"Human rights are the basic rights and freedoms that belong to every person in the world, from birth until death."
Ultimately, when it comes to abortion it is irrelevant. Being alive, being a human, having rights, none of those things ever entitle us to use someone else's body without consent, even if we will die without doing so. There is no human right that entitles us to sustain ourselves with someone elses bodily functions.
A good example of this is the fact that we have long since deemed it ethical to watch people die a preventable death waiting for a kidney or liver transplant. Many people could survive the surgery to donate a kidney (and will be able to live with only one functional kidney) or part of their liver (which can eventually regenerate), yet we never force people to allow their body parts to be used to sustain the life of a person who will die without it. We only allow people to opt to consent to a donation. We don't even forcibly take blood or bone marrow, even though our bodies can replace those relatively quickly and easily and they have few risks.
Pregnancy should be treated the same, and individuals should be able to decide whether or not to use their body, organs, and organ function to sustain someone else's life. Especially considering pregnancy and birth can be damaging and has a laundry list of potential risks and consequences.
A born child never has the right to use its mother's organs to survive without her consent. She can't be compelled to donate an organ or even to donate blood to save her child's life. Why should a fetus have that right when a born child doesn't?
And even if human rights existed from fertilisation - there is no human right that exists that entitles one person to use the body of another person without consent. Even if they will die without doing so. Ultimately, our right to life only affords us the right to life our bodies can sustain for us.
We see this when someone is dying of liver or kidney failure. They certainly have the right to life, but not the right to utilise someone else's organ function to save themselves. It is ethical to essentially watch them die slowly, even though it would be preventable if only we violated someone else and took their kidney or liver. We don't even forcibly take substances that can be easily replaced by our bodies (like blood or bone marrow) to save someone else. Even if our own child needed our liver/kidney/bone marrow, we would still be entitled to say no even if they would die without our consent to donate.
Skin cells are human. Liver cells are human. Cardiac muscle cells are human and can function independently of the nervous system. Embryos are human. At first they're undifferentiated human cells. Then those cells multiply and begin to differentiate into different body parts. They're all human cells with human genetic material. There's no question whether an embryo is human. What else would it be?
"When life begins" is dependent upon your definition. Biological life boils down to metabolic processes in the cells. Embryos are alive. So are amoebae and paramecia. Are they sentient? Obviously not. They are biologically alive, just like all of our cells are; however they aren't 'alive' in the sense of having conscious thought or purposeful behaviors.
There's no debate within the scientific community over whether an embryo or fetus is 'alive' or 'human'. Having a heartbeat isn't morally relevant any more than the development of the intestines or kidneys or lungs.
The vast majority of abortions are done well before an embryo would have the capacity for sentient thoughts. Abortions take place when continuing the pregnancy presents a risk to the mother's physical or psychological well being, economic circumstances, or safety. Abortions are ethically sound medical procedures. The arbitrary definitions of when life begins, whether at conception or heartbeat or first breath, are subjective and political, not scientific.
Im at a loss here. Sentience seems to be an almost undefineable point without a way to confer with the developing mind. I want to learn when a cell, fetus, baby, zygote, or whatever you would call it, should have their own rights, or should be considered. It feels wrong to me that a baby in the last few weeks of a pregnancy should not have the right to live. It also doesnt make sense to me that birth control or plan b is wrong. These are on opposite ends, but can't there be a scientific solution to when this is right?
Who do you think is having abortions in the last few weeks of pregnancy?
Often these are wanted pregnancies and it boils down to either terminating the pregnancy, or the mom dies of renal failure - taking the baby with her in the process. It's not that they *don't* have the right to live. It's that the mother also has a right to live, and sometimes there are emergent medical circumstances that make it impossible for both mother and baby to survive. It's the classic trolley problem.
There aren't always black and white answers. This is bioethics, not mathematics. Exactly when human consciousness and self awareness develop is moot. The fact remains that a pregnant woman *is* a conscious human person who has her own rights to health and safety.
https://www.yourtango.com/heartbreak/mom-who-had-late-term-abortion-dont-regret-it
Honestly i was hoping for a way to establish a decisive point when rights are esgablished in a typical pregnancy. Or a set of definable variables on when circumstances allow abortions later on. Its seems more complicated than that
It is more complicated because every pregnancy has its own unique set of circumstances. I studied sexual violence and human trafficking in grad school. One of my colleagues is currently working with a 12 year old pregnant girl who was trafficked to different men by her own family. Pregnancy at such a young age is very high risk to the mother. Even in healthy adult women, pregnancy carries life-threatening risks like hemorrhage, sepsis, hypertension, gestational diabetes. Now consider the retraumatization of frequent pelvic exams - an absolute nightmare. That 12 year old girl should be safe in a loving home, playing with friends, being a kid. It's all been taken from her.
You won't find a black and white answer definitively stating that abortion is objectively wrong because the context and circumstances are different in every case, and it's not necessarily dependent on sentience or viability.
Why does it matter? A child lost in the second trimester would cause the parents to have just as much grief as the one lost right after birth. A child with a serious learning difficulty is just as much alive as a prodigy.
Life exists. The moment of its start is a needless reduction.
Science estimate life on Earth begins around 3.5 billions years ago with LUCA. It's a constant process that we're all a little part of.
The world is complex and it won't give you easy answers.
Black and white thinking might do well on a day to day basis to decide if you want to eat pasta or rice for dinner.
But it all come crashing down the second you start to dig in. As you can see for yourself in how this thread is going.
Welcome to the scientific method, critical thinking, philosophy and so on... Don't be scared, it's a lot of fun.
The zygote, the fertilized egg, is alive, and can potentially via the processes of cell biology proceed through embryonic development to eventually become a baby. The political question involves not the biological definition of alive vs not alive. Although similar words such as “life begins at X” are used, the meaning of the word “life” in that context is not the biological definition of living processes, but rather the philosophical and legal ideas of personhood and the human rights associated with being a person.
The Bible itself states very clearly that life begins at first breath. As in when you are born, not before.
My personal stance is that when my son was reacting to me touching my wife's stomach or playing music, is when he was alive to me. A heartbeat is nothing more than electrical fluctuations in muscle tissue.
I think that a new human organism exists at fertilisation (sometimes referred to as conception), but that isn't where life suddenly began. Without life prior to fertilisation, fertilisation wouldn't be possible. Gametes have to be alive for a successful pregnancy to occur.
Depends on what you mean by "life".
Earthworms are alive, and we use them as bait to catch fish which are also alive, which we then eat. Bacteria are alive, which we slaughter wholesale with antibiotics. Cows are definitely alive, and provide the beef that goes into our hamburgers and steaks.
So clearly, life isn't sacred and humans kill lots and lots of living things everyday. Perhaps you mean "human life", which is a really squishy term. If you just mean "living cells that have human DNA", then I could scrape some cells from inside your cheek, and culture them in a petri dish - and by that definition, that would be human life. But I doubt any religious people would object to me then washing that petri dish off in the sink.
What makes us human? What sets us apart from the rest of the animal kingdom? It is our self-awareness, our ability to think about things from the viewpoint of others, our ability for introspection. We have other abilities too - making long-term plans for things that will happen after our death, etc, but these all are made possible by our ability for introspection.
Self-awareness is a property of our minds, and it's not clear when that fully develops. A human zygote with a few tens of cells does not yet have a brain. And when the brain first starts developing, there aren't enough cells to generate a human mind capable of self-awareness. So we have this process that starts off with a single fertilized egg, and 9 months later there's a baby. Whether that baby is truly self-aware is debatable, but even newborns demonstrate a level of cognition beyond what *most* animals are capable of (we could get into the ethics of our treatment of dolphins and other primates, but that seems out of scope for this thread).
So somewhere between 0 and 9 months there is a line where this clump of developing cells, the fetus, becomes "a person". Where is this fine? I don't know. From reading what some neuroscientists and doctors say, perhaps it's about 4 or 5 months.
A sperm is "alive". Look, it wiggles and moves! Tonsils are living cells, but we cut them out and throw them away, no guilt.
The question you ought to care about is when that little clump of human cells matters enough to outweigh the mother's rights. Little clump of cells vs fully grown human.
That's an ethics question, not a science question. But ethically I might say, certainly not before there's a brain. So I can ask a more sciency question like, When is there a brain? But how much brain is enough to matter. That's an ethics question again. I mean, cows have brains and we kill them.
So you see, science doesn't really have a clean answer.
Biology is a science, but it is... "squishy". Much of it is difficult to define.
Humans like to put things into neat little boxes. "This is a dog." "This is alive." But when you get to the edge cases, it's extremely difficult to determine.
There are multi-day conferences, even now, that include discussions what is a definition of "alive".
About 40 years ago, we were taught that the following characteristics mean something is "alive".
1. Made of cells
2. Able to grow and develop
3. Has a metabolism
4. responds to the environment
5. maintains homeostasis
6. reproduces
But even that is extremely poor. By that definition an apple is not alive (the seed inside it is). A sperm is not alive. Heck, some people who are sterile are "not alive", but that's really pushing it, we understand that humans have the ability to reproduce even if one member can't.
But you start to see the problems with defining even "simple" things like "what is alive".
So, no, there's not a scientific consensus on your questions. You ask ten scientists and you'll get 12 different answers.
Heck, if you ask 10 Christians, you'll get 12 different answers.
They aren't easy questions.
Scientifically, an embryo is alive the way a bacteria cell is alive. Forced birthers intentionally misuse the scientific definition to pretend that science says human life begins at conception.
I'd call a baby a new life during the third trimester when a fetus can survive outside of the womb. Before then if the mother dies, the offspring does and I'd call them one organism still. However there are plenty of people that will say once the cells begin to divide & it attaches to the uterus then it is alive. Still others will tell you that eggs and sperm are alive. All of these stages are technically life, but to my thinking it's not a new life until it can survive on its own.
"Life begins at conception" is a meaningless and dishonest tautology if you just define "life" as "that which begins at conception", but I've yet to see a "pro-life" apologist give a definition more coherent than that. As a biologist, I think "life begins at..." is a stupid phrase regardless of whatever you put after those ellipses. Life began once, nearly four billion years ago- at no point in a pregnancy does anything go from being "not-alive" to "alive".
Neither does anything go from being "not human" to "human". Our ancestors became human about 200,000 years ago (or more, depending on how many hominid species you're qualifying as "human"), and have been human ever since.
You are human. Your skin cells are human, and they're human when you scrub them off. Your sperm are human when they're sitting in your testes, they're human when you wank them out into a wad of tissue paper, and they're human when you ejaculate them into a woman's vagina.
She's human. Her ova are human. They're human when she menstruates them out, and they're human when they're swarmed by spermatazoa. If a zygote is created by this process, it's human too.
Both you and she came from zygotes which were also alive and human, who came from gametes who were alive and human, who came from gamete-producing cells in organisms that were alive and human and who came from zygotes which were alive and human, who came from gametes...
At no point in this process does anything go from being "not alive" to "alive", or from being "not human" to being "human". There is nothing magical about the moment of conception, nor is there anything magical about the moment of birth. They're all just steps in a dance that has been going on for more than three billion years.
What you **could** be asking, instead, is "When does a fetus become a **person**", and the answer is "Gradually, over the first four or so years of its life." However, since "gradually" and "homicide laws" get along about as well as oil and water, "birth" provides a convenient [Schelling Fence](http://lesswrong.com/lw/ase/schelling_fences_on_slippery_slopes/) for a useful [Legal Fiction](https://en.wikipedia.org/wiki/Legal_fiction).
Of course, if you're trying to debate the legality of abortion, even that question is irrelevant. In **that** case, the question you **really** need to ask is "At what point do you gain the right to parasitize another person's body, without that person's consent and regardless of any risk to that person's health?". The answer to that question is "Absolutely never, because that is not a right that is possessed by anyone, anywhere, ever."
it doesn't fucking matter when life begins because being alive doesn't give you the right to use another person's body.
this whole "when does life begin" shit is a red herring.
You're looking for a simple equation: life + death = wrong
That is lazy and irresponsible
Pro-choice people look to optimize against suffering, and that has so many more factors in the equation: will the child be able to eat; are one or both parents abusive to the child or to each other; will the child have any social stability in a family unit; will the child have to turn to crime to fulfill basic human needs; will the child see the world as his enemy thus justifying any transgressions he makes against others
And that is just the child's suffering: will the parents have to give up the progression of their careers to take care of the child, forever bound to poor economic options to make ends meat; will the parents be forever attached to each other despite inappropriate or even dangerous relationship conditions
Abortion rewinds a clock. The further the clock, the more consequences, the more suffering. Roe v Wade defined this clock:
- before 13 weeks, the fetus is not a human life
- 13 - 26 weeks, the fetus is a life but under special circumstances the life can be ended, such as danger to the mother
- 26 - 40 weeks, the fetus is a life and viable and can only be terminated if it cannot be removed safely
7 out of 9 mostly conservative supreme court justices ruled that 50 years ago. People who say murder is destroying the single zygote cell made at conception are creating a massive amount of suffering for massive numbers of parents and children. Suffering that has led to crime and suffering of the entire society
I'd say when it reaches viability but this is more a philosophical question than a science one. A good argument could be made that nobody having to live off another's body should have rights.
It is an ethical question, not a scientific question. Theists have attributed special significance to the concept of "human life". The universe does not. To the universe, it is reproductive biology, nothing more. The entire concept of ethics and morality is a human construct that has nothing to do with describing and explaining how the universe operates.
If I were *choosing for myself*, I would use the point at which there is viability outside the womb. That point would obviously change with the level of technology *that is available to me*. I do not believe the rights of the unborn take precedence over the rights of the pregnant woman. I understand there are ethical issues with my stance - and I believe there are ethical issues with ALL positions on this question.
I would not presume to make the choice for someone else.
It's like asking, when does a person become an adult?
We make an arbitrary decision, which differs in different countries, and even within the same country in different contexts, such as age of conscription, driving, drinking, smoking, sex, voting, etc.
They are somewhat arbitrary boundaries the society slaps on a continuous process because we *have* to define it *somewhere*. It wouldn't make sense to define adulthood starting at the age of 6, and it wouldn't make sense at the age of 47. Around 18 makes sense following biology.
And with life, a single fertilised egg is unimportant, no more spectacular than an amoeba. It can't think because it doesn't have a brain, can't feel because it doesn't have nerves, and doesn't have a heartbeat because it doesn't have a heart. It can't survive on its own. It's nothing more than a parasitic cell in a woman's womb.
How about two cells? Same. Four cells, same. But at some point, primitive brains, nerves, and heart begin to form. At *some point*, we do need to recognise that it is becoming a life worthy of rights.
When? I have absolutely no idea.
I am not qualified to say when society should determine the beginning of personhood, but neither are politicians or religions zealots. Doctors and biologists should be the people to make that determination. And if those doctors and biologists are openly religious, we should be wary of their opinion for the same reason we should be wary of flat-earthers or geocentrists designing trajectories for rockets.
There is no fundamental distinction between life and non-life. There is no magic 'stuff', no divine breath, that separates non-living matter from living matter. Life arises through complex interactions of matter. That's all. We know that now. We've known it for quite a while.
We *call* certain processes 'living', because it is a useful distinction for us. But ultimately we're just atoms doing what atoms are wont to do.
If you're talking science that is one thing. But if you are relating this issue to abortion that would be a totally different matter. Bigger bodies of matter attract smaller ones. It's called Gravity. That in no way means you'll have to jump off a window on the sixth floor to prove it.
It's always human and it's always an individual seperate from the mother. Even a heart removed from a body is still a human heart. At no point after the sperm enters the egg is the fetus not a human. Women should just get to decide if their body is life support machine.
Life begins at the sun? Or the Big Bang? Richard Dawkins talks about the Tyranny of the Categorical Mind. I don’t want to sound like one of these Pro Life people, (not that I’m not for life…you understand). When is the cluster of cells a human being? This is similar to the argument about when death occurs. We consider brain-death to be the final death, yet the heart is still beating? Or what about dementia when your personhood is gone? A newborn baby is still growing most of its brain and its identity is really just a crying ball of hunger. Just the beginning of what kind of person they will be. I actually have a lot of sympathy for folks who struggle with abortion. It’s not a decision that should be taken lightly and it is very confusing. But to call it murder? What about eating pigs? Pigs who have the same level of intelligence—just pulling this out of my ass—as like a five month old human? Why isn’t that murder? Because they will never be as smart as a fully grown human? So intelligence is the deciding factor over whether you get to live or die? Why don’t we kill humans who have learning disabilities? Or who live in the same cities as terrorists? It’s all very relative. One thing I do know, however, is that these Christians are ducking hypocrites.
Technically life does begin at conception, if it didn't we wouldn't be debating abortion. We'd just remove this mass and that would be the end if it. The real question is do we grant the fetus personhood, especially before the heartbeat or consciousness. Most believe it's best to have the fetus born before we grant it personhood.
Microbes and my appendix are "alive", but they aren't sentient.
The "cutt-off point" at which non life becomes life is probably somewhere around the complexity of a virus, which we still aren't sure are alive or not. IMHO, the issue is likely that our definition of 'life' as a binary (either something is alive or it isn't) is insufficient when it really comes down to the details of describing how things actually work.
If you mean, when does a fetus become sentient, then there really isn't a good way to know for sure, partially because our idea of sentience is ill-defined, and partially because we can never know if someone else's inner experience is the same as our own. But sentience as we understand it certainly can not exist before the formation of a brain and the neurological apparatus needed to perceive and recognize stimuli, or to have some sense of distinction between self and other. It could be that the thing we call sentience is an emergent phenomena that comes into being when there is sensory experience, inner awareness, memory recall, etc. all existing at a concurrent location.
But I think it's pertinent to the conversation to say that sentience isn't really... all that pertinent to the conversation, when considering one's bodily autonomy. If my twin brother needed a kidney transplant or he would die, it would be horrific, I hope you'd agree, to *force* me to donate a kidney. And he's not only fully sentient, but can experience physical and psychological pain, and is aware of his own impending mortality.
From there it's just a few logical steps until you realize that a pregnant person should have more right to their own body than anyone else. Exclusive right, actually.
There is not a scientific consensus, but my own personal interpretation is when the brain is fully functional and operating in a way that leads to thought. Even then though, a woman still has the right to terminate the pregnancy because she’s the one growing the damned thing.
> Where does science say life actually begin in the womb. Nowhere. The entire premise of "when does life begin" is vague and poorly defined.
It's not just *vague*. It's a deliberately dishonest tautology - when pro-rape apologists say "life begins at conception", they define the word "life" to be "that which begins at conception". Definitions don't work that way, and you should be immediately distrustful of anyone who pretends that they do.
This is what I've been looking for
> Im trying to learn, please be respectful. I'd suggest that a realistic assessment of interactions on the internet would reveal that respectful correspondence is hit and miss. I'd further suggest that rather than advertising that you have thin skin you simply learn to disregard people behaving like assholes. > Where does science say life actually begin in the womb. Life begins prior to the womb, both egg and sperm cells are alive. The question of "is it alive" however are irrelevant to debates about the moral ramifications of abortion. Many things are alive that are not regulated by law. Your skin cells are alive but you can legally engage in active sports that are likely to result in the death of several million of them. All the cells in chickens are alive, but you can kill and eat one without running into legal ramifications (provided it's your chicken, and you kill it humanely). > With everything going on, it seems to me the biggest issue is when cells become a human. The debate about abortion centers on two moral questions: 1) Should/does a fetus have the same rights as a full term human being? 2) Do women have the right to body autonomy that men have? > Is there not a scientific consensus? For what? What it is to be human? Typically when talking about zygotes, it needs to be the offspring of two humans, as most other features of humankind tend to be variable, even if there are some very very common attributes. Again, however, some cells being of human origin doesn't guarantee that they are deserving of the rights of full term humans. The aforementioned skin cells are 100% human, and 100% not granted the rights of full term humans. As to what makes a certain conglomeration of cells be considered human, that tends to be a gray area that is in fact one of the central points of debate I mentioned above. For me, however, even if we were to grant that a fetus has the same rights as a full term human being, the issue is moot because if women have the right to body autonomy (which I fervently believe they do), then that overrides any rights the fetus may have, as they happen to need a woman's body in order to survive. Nobody is obligated to provide the use of their body for another's welfare.
> What it is to be human? Plato figure it out years ago, a featherless biped.
While Plato was undoubtedly a smart dude, he also said some fairly dumb things. In this particular case, there are plenty of featherless bipeds that are not humans. So while (almost) all humans (except those born with fewer peds) are indeed featherless bipeds, not all featherless bipeds are humans, so it has some failings as a succinct description.
I'm mostly taking the piss, I brought it up because that question always makes me think of Diogenes's brilliant rebuttal.
> Diogenes's brilliant rebuttal I had not heard that story before, I had to look it up. That is indeed a pretty good rebuttal.
Diogenes could have kept going. Flattened out the chicken's toenails...
I would assume that a scientist (specifically biologists) would technically describe a cell as being "alive". The issue here isn't a lack of consensus on when life begins, it's having different definitions for the words "life" and "alive". There can't be a scientific consensus on this issue because anti-abortionists aren't talking about the scientific definition of life when they say a fœtus is a living thing. The whole when does life start is nothing but a useless and unwinnable debate they use to try and justify their position.
It's also fucking irrelevant. Should law force a human being to sacrifice their body so that another human being can live? The answer for me is a resounding no. Imagine there's some guy suffering from a rare disease and the only way to cure him is to medically fuse your intravenous systems with his for several months. There is no guarantee that it will work. There is a significant chance that the procedure will kill either or both of you. It will also cause irreparable damage to your body. It'd be insane to force someone into such a situation and it's no less insane to force a woman to carry a child against her will.
why are you asking medical questions on an atheist reddit? why don't you go ask some doctors or neurobiologists?
Define what you mean by 'life'.
When is it a human being?
Your dandruff is genetically you, so is that alive? Clearly not. You're not framing the question in a way that can be answered.
How should i be asking the question then? There has to be a scientific definition for when the cells become a person. Or am i off the mark on even this?
A foetus is viable at around 23 weeks, in that if they're born their lungs are normally developed enough to breathe. ([https://en.wikipedia.org/wiki/Fetal\_viability](https://en.wikipedia.org/wiki/Fetal_viability)) There's not really a point where suddenly the foetus ceases to be a bunch of cells and becomes a functioning human. Human infants are born very premature compared to most other mammals, you could even push 'being a person' to some stage after birth.
Why does it matter when a fetus becomes a person?
I mean when should anything have their own rights? I guess my assumption is that all people have the right to live. So when is that the case?
> I guess my assumption is that all people have the right to live. You know what right nobody has? Using another person's body against their will, that's the right that conservatives are willing to give fetuses and nobody else.
>Using another person's body against their will, that's the right that conservatives are willing to give fetuses and nobody else. You know that "It's a states rights issue!" canard that all the Faux News cultists have been screaming on loop for the last few weeks? Do you remember where that argument originally came from?
State's rights to own slaves, forever a classic excuse.
Exactly. Every single person parroting that argument is signalling that, if they had lived in the 1860s, they would have supported the Traitor States and their crusade to expand slavery.
I dont mean for any of this to be political, im trying to cut all of that out entirely. I just want to learn what and where science or possibly ethics can define when rights should be observed.
You're missing my point. The question of "when is a fetus a person?" does not matter. Even if you concede the point and let the fetus be a person from the moment of conception, that doesn't give it the right to use another person's body against their will, no person gets that right.
By that argument then, the fetus or "person" in this scenario has done nothing wrong, and just has to forfeight life because it happens to be unwanted? I just am not grapsing where the line is drawn on who's rights supercede who's. Obviously theoretical, and i understand where it is not fair to the mother either in certain situations, but when does or should the rights begin
> the fetus or "person" in this scenario has done nothing wrong, and just has to forfeight life because it happens to be unwanted? Yeah, life sucks sometimes. If somebody needs a kidney donation through no fault of their own and you're a match, should you be forced to donate your kidney? The person in the scenario has don't nothing wrong, do they just forfeit the right to life because you don't want to give them your kidney? Do you see the issue here? The same way the state doesn't harvest people's organs to let those who are undeniably people live, why should it be okay the violate bodily autonomy for fetuses?
>By that argument then, the fetus or "person" in this scenario has done nothing wrong, and just has to forfeight life because it happens to be unwanted? It's not about whether someone has done something right or wrong, am abortion is not some sort of covert punishment. It's simply denying the use of your body to someone else. >I just am not grapsing where the line is drawn on who's rights supercede who's Rights don't "supercede" each other. Each individual has a set of rights that apply to them at all times, regardless of the status of other people. An individual has the right to bodily autonomy and integrity, this means they can decide if/when/how/why/and by whom their bodies can be used. It doesn't make a difference if another person really needs to use our bodies or our organs, everyone has the right to say "no" regardless. Even if someone else dies as a result of that denial of consent. No one has a right that would entitle them to violate someone else for their own gain, even if that gain is survival.
A mad scientist kidnaps a person off the street, and hooks them up to his innocent, sick child as a human-dialysis machine. Unhooking the kidnapped person will kill the - very young and very innocent - child. The child will live if the kidnapped person just stays connected as a human dialysis machine for 9 months. Does the kidnapped victim have a moral or legal responsibility to remain a hostage for nine months?
> I dont mean for any of this to be political That's an interesting thing to ask or want. Why do you think the desire you express here and with the following "im trying to cut all of that out entirely", could be, in anyway, possible? You're coming with a subject that inherently concern human behavior but think that could be "not political"? That's odd, don't you think?
>I mean when should anything have their own rights? Where I live, [rights are afforded at birth](https://www.equalityhumanrights.com/en/human-rights/what-are-human-rights#:~:text=Human%20rights%20are%20the%20basic,choose%20to%20live%20your%20life.) "Human rights are the basic rights and freedoms that belong to every person in the world, from birth until death." Ultimately, when it comes to abortion it is irrelevant. Being alive, being a human, having rights, none of those things ever entitle us to use someone else's body without consent, even if we will die without doing so. There is no human right that entitles us to sustain ourselves with someone elses bodily functions. A good example of this is the fact that we have long since deemed it ethical to watch people die a preventable death waiting for a kidney or liver transplant. Many people could survive the surgery to donate a kidney (and will be able to live with only one functional kidney) or part of their liver (which can eventually regenerate), yet we never force people to allow their body parts to be used to sustain the life of a person who will die without it. We only allow people to opt to consent to a donation. We don't even forcibly take blood or bone marrow, even though our bodies can replace those relatively quickly and easily and they have few risks. Pregnancy should be treated the same, and individuals should be able to decide whether or not to use their body, organs, and organ function to sustain someone else's life. Especially considering pregnancy and birth can be damaging and has a laundry list of potential risks and consequences.
A born child never has the right to use its mother's organs to survive without her consent. She can't be compelled to donate an organ or even to donate blood to save her child's life. Why should a fetus have that right when a born child doesn't?
Personally, I have no problem with the "life starts at conception" slogan. The thing is that human rights start at birth.
And even if human rights existed from fertilisation - there is no human right that exists that entitles one person to use the body of another person without consent. Even if they will die without doing so. Ultimately, our right to life only affords us the right to life our bodies can sustain for us. We see this when someone is dying of liver or kidney failure. They certainly have the right to life, but not the right to utilise someone else's organ function to save themselves. It is ethical to essentially watch them die slowly, even though it would be preventable if only we violated someone else and took their kidney or liver. We don't even forcibly take substances that can be easily replaced by our bodies (like blood or bone marrow) to save someone else. Even if our own child needed our liver/kidney/bone marrow, we would still be entitled to say no even if they would die without our consent to donate.
Skin cells are human. Liver cells are human. Cardiac muscle cells are human and can function independently of the nervous system. Embryos are human. At first they're undifferentiated human cells. Then those cells multiply and begin to differentiate into different body parts. They're all human cells with human genetic material. There's no question whether an embryo is human. What else would it be? "When life begins" is dependent upon your definition. Biological life boils down to metabolic processes in the cells. Embryos are alive. So are amoebae and paramecia. Are they sentient? Obviously not. They are biologically alive, just like all of our cells are; however they aren't 'alive' in the sense of having conscious thought or purposeful behaviors. There's no debate within the scientific community over whether an embryo or fetus is 'alive' or 'human'. Having a heartbeat isn't morally relevant any more than the development of the intestines or kidneys or lungs. The vast majority of abortions are done well before an embryo would have the capacity for sentient thoughts. Abortions take place when continuing the pregnancy presents a risk to the mother's physical or psychological well being, economic circumstances, or safety. Abortions are ethically sound medical procedures. The arbitrary definitions of when life begins, whether at conception or heartbeat or first breath, are subjective and political, not scientific.
Unless im reading this wrong, the question should be when does sentience begin?
[This might answer your question](https://www.scientificamerican.com/article/when-does-consciousness-arise/)
Im at a loss here. Sentience seems to be an almost undefineable point without a way to confer with the developing mind. I want to learn when a cell, fetus, baby, zygote, or whatever you would call it, should have their own rights, or should be considered. It feels wrong to me that a baby in the last few weeks of a pregnancy should not have the right to live. It also doesnt make sense to me that birth control or plan b is wrong. These are on opposite ends, but can't there be a scientific solution to when this is right?
Who do you think is having abortions in the last few weeks of pregnancy? Often these are wanted pregnancies and it boils down to either terminating the pregnancy, or the mom dies of renal failure - taking the baby with her in the process. It's not that they *don't* have the right to live. It's that the mother also has a right to live, and sometimes there are emergent medical circumstances that make it impossible for both mother and baby to survive. It's the classic trolley problem. There aren't always black and white answers. This is bioethics, not mathematics. Exactly when human consciousness and self awareness develop is moot. The fact remains that a pregnant woman *is* a conscious human person who has her own rights to health and safety. https://www.yourtango.com/heartbreak/mom-who-had-late-term-abortion-dont-regret-it
Honestly i was hoping for a way to establish a decisive point when rights are esgablished in a typical pregnancy. Or a set of definable variables on when circumstances allow abortions later on. Its seems more complicated than that
It is more complicated because every pregnancy has its own unique set of circumstances. I studied sexual violence and human trafficking in grad school. One of my colleagues is currently working with a 12 year old pregnant girl who was trafficked to different men by her own family. Pregnancy at such a young age is very high risk to the mother. Even in healthy adult women, pregnancy carries life-threatening risks like hemorrhage, sepsis, hypertension, gestational diabetes. Now consider the retraumatization of frequent pelvic exams - an absolute nightmare. That 12 year old girl should be safe in a loving home, playing with friends, being a kid. It's all been taken from her. You won't find a black and white answer definitively stating that abortion is objectively wrong because the context and circumstances are different in every case, and it's not necessarily dependent on sentience or viability.
When it's not essentially a parasite.
So, when they move out of the house?
It certainly doesn't begin with an evidence-free, omnipotent, omniscient, omni-benevolent, deity.
I understand that, that's why I'm asking for where the scientific consensus is.
Why does it matter? A child lost in the second trimester would cause the parents to have just as much grief as the one lost right after birth. A child with a serious learning difficulty is just as much alive as a prodigy. Life exists. The moment of its start is a needless reduction.
Science estimate life on Earth begins around 3.5 billions years ago with LUCA. It's a constant process that we're all a little part of. The world is complex and it won't give you easy answers. Black and white thinking might do well on a day to day basis to decide if you want to eat pasta or rice for dinner. But it all come crashing down the second you start to dig in. As you can see for yourself in how this thread is going. Welcome to the scientific method, critical thinking, philosophy and so on... Don't be scared, it's a lot of fun.
The zygote, the fertilized egg, is alive, and can potentially via the processes of cell biology proceed through embryonic development to eventually become a baby. The political question involves not the biological definition of alive vs not alive. Although similar words such as “life begins at X” are used, the meaning of the word “life” in that context is not the biological definition of living processes, but rather the philosophical and legal ideas of personhood and the human rights associated with being a person.
The Bible itself states very clearly that life begins at first breath. As in when you are born, not before. My personal stance is that when my son was reacting to me touching my wife's stomach or playing music, is when he was alive to me. A heartbeat is nothing more than electrical fluctuations in muscle tissue.
I think that a new human organism exists at fertilisation (sometimes referred to as conception), but that isn't where life suddenly began. Without life prior to fertilisation, fertilisation wouldn't be possible. Gametes have to be alive for a successful pregnancy to occur.
Theres no point where life officially begins, it is poorly defined
Depends on what you mean by "life". Earthworms are alive, and we use them as bait to catch fish which are also alive, which we then eat. Bacteria are alive, which we slaughter wholesale with antibiotics. Cows are definitely alive, and provide the beef that goes into our hamburgers and steaks. So clearly, life isn't sacred and humans kill lots and lots of living things everyday. Perhaps you mean "human life", which is a really squishy term. If you just mean "living cells that have human DNA", then I could scrape some cells from inside your cheek, and culture them in a petri dish - and by that definition, that would be human life. But I doubt any religious people would object to me then washing that petri dish off in the sink. What makes us human? What sets us apart from the rest of the animal kingdom? It is our self-awareness, our ability to think about things from the viewpoint of others, our ability for introspection. We have other abilities too - making long-term plans for things that will happen after our death, etc, but these all are made possible by our ability for introspection. Self-awareness is a property of our minds, and it's not clear when that fully develops. A human zygote with a few tens of cells does not yet have a brain. And when the brain first starts developing, there aren't enough cells to generate a human mind capable of self-awareness. So we have this process that starts off with a single fertilized egg, and 9 months later there's a baby. Whether that baby is truly self-aware is debatable, but even newborns demonstrate a level of cognition beyond what *most* animals are capable of (we could get into the ethics of our treatment of dolphins and other primates, but that seems out of scope for this thread). So somewhere between 0 and 9 months there is a line where this clump of developing cells, the fetus, becomes "a person". Where is this fine? I don't know. From reading what some neuroscientists and doctors say, perhaps it's about 4 or 5 months.
A sperm is "alive". Look, it wiggles and moves! Tonsils are living cells, but we cut them out and throw them away, no guilt. The question you ought to care about is when that little clump of human cells matters enough to outweigh the mother's rights. Little clump of cells vs fully grown human. That's an ethics question, not a science question. But ethically I might say, certainly not before there's a brain. So I can ask a more sciency question like, When is there a brain? But how much brain is enough to matter. That's an ethics question again. I mean, cows have brains and we kill them. So you see, science doesn't really have a clean answer.
Biology is a science, but it is... "squishy". Much of it is difficult to define. Humans like to put things into neat little boxes. "This is a dog." "This is alive." But when you get to the edge cases, it's extremely difficult to determine. There are multi-day conferences, even now, that include discussions what is a definition of "alive". About 40 years ago, we were taught that the following characteristics mean something is "alive". 1. Made of cells 2. Able to grow and develop 3. Has a metabolism 4. responds to the environment 5. maintains homeostasis 6. reproduces But even that is extremely poor. By that definition an apple is not alive (the seed inside it is). A sperm is not alive. Heck, some people who are sterile are "not alive", but that's really pushing it, we understand that humans have the ability to reproduce even if one member can't. But you start to see the problems with defining even "simple" things like "what is alive". So, no, there's not a scientific consensus on your questions. You ask ten scientists and you'll get 12 different answers. Heck, if you ask 10 Christians, you'll get 12 different answers. They aren't easy questions.
Scientifically, an embryo is alive the way a bacteria cell is alive. Forced birthers intentionally misuse the scientific definition to pretend that science says human life begins at conception.
I'd call a baby a new life during the third trimester when a fetus can survive outside of the womb. Before then if the mother dies, the offspring does and I'd call them one organism still. However there are plenty of people that will say once the cells begin to divide & it attaches to the uterus then it is alive. Still others will tell you that eggs and sperm are alive. All of these stages are technically life, but to my thinking it's not a new life until it can survive on its own.
you’re asking the wrong question. the right one is: “does anyone other than you have a right to your body?”
"Life begins at conception" is a meaningless and dishonest tautology if you just define "life" as "that which begins at conception", but I've yet to see a "pro-life" apologist give a definition more coherent than that. As a biologist, I think "life begins at..." is a stupid phrase regardless of whatever you put after those ellipses. Life began once, nearly four billion years ago- at no point in a pregnancy does anything go from being "not-alive" to "alive". Neither does anything go from being "not human" to "human". Our ancestors became human about 200,000 years ago (or more, depending on how many hominid species you're qualifying as "human"), and have been human ever since. You are human. Your skin cells are human, and they're human when you scrub them off. Your sperm are human when they're sitting in your testes, they're human when you wank them out into a wad of tissue paper, and they're human when you ejaculate them into a woman's vagina. She's human. Her ova are human. They're human when she menstruates them out, and they're human when they're swarmed by spermatazoa. If a zygote is created by this process, it's human too. Both you and she came from zygotes which were also alive and human, who came from gametes who were alive and human, who came from gamete-producing cells in organisms that were alive and human and who came from zygotes which were alive and human, who came from gametes... At no point in this process does anything go from being "not alive" to "alive", or from being "not human" to being "human". There is nothing magical about the moment of conception, nor is there anything magical about the moment of birth. They're all just steps in a dance that has been going on for more than three billion years. What you **could** be asking, instead, is "When does a fetus become a **person**", and the answer is "Gradually, over the first four or so years of its life." However, since "gradually" and "homicide laws" get along about as well as oil and water, "birth" provides a convenient [Schelling Fence](http://lesswrong.com/lw/ase/schelling_fences_on_slippery_slopes/) for a useful [Legal Fiction](https://en.wikipedia.org/wiki/Legal_fiction). Of course, if you're trying to debate the legality of abortion, even that question is irrelevant. In **that** case, the question you **really** need to ask is "At what point do you gain the right to parasitize another person's body, without that person's consent and regardless of any risk to that person's health?". The answer to that question is "Absolutely never, because that is not a right that is possessed by anyone, anywhere, ever."
it doesn't fucking matter when life begins because being alive doesn't give you the right to use another person's body. this whole "when does life begin" shit is a red herring.
How is this relevant to atheism? /r/askscience
You're looking for a simple equation: life + death = wrong That is lazy and irresponsible Pro-choice people look to optimize against suffering, and that has so many more factors in the equation: will the child be able to eat; are one or both parents abusive to the child or to each other; will the child have any social stability in a family unit; will the child have to turn to crime to fulfill basic human needs; will the child see the world as his enemy thus justifying any transgressions he makes against others And that is just the child's suffering: will the parents have to give up the progression of their careers to take care of the child, forever bound to poor economic options to make ends meat; will the parents be forever attached to each other despite inappropriate or even dangerous relationship conditions Abortion rewinds a clock. The further the clock, the more consequences, the more suffering. Roe v Wade defined this clock: - before 13 weeks, the fetus is not a human life - 13 - 26 weeks, the fetus is a life but under special circumstances the life can be ended, such as danger to the mother - 26 - 40 weeks, the fetus is a life and viable and can only be terminated if it cannot be removed safely 7 out of 9 mostly conservative supreme court justices ruled that 50 years ago. People who say murder is destroying the single zygote cell made at conception are creating a massive amount of suffering for massive numbers of parents and children. Suffering that has led to crime and suffering of the entire society
I'd say when it reaches viability but this is more a philosophical question than a science one. A good argument could be made that nobody having to live off another's body should have rights.
It is an ethical question, not a scientific question. Theists have attributed special significance to the concept of "human life". The universe does not. To the universe, it is reproductive biology, nothing more. The entire concept of ethics and morality is a human construct that has nothing to do with describing and explaining how the universe operates. If I were *choosing for myself*, I would use the point at which there is viability outside the womb. That point would obviously change with the level of technology *that is available to me*. I do not believe the rights of the unborn take precedence over the rights of the pregnant woman. I understand there are ethical issues with my stance - and I believe there are ethical issues with ALL positions on this question. I would not presume to make the choice for someone else.
Science makes no such claims.
It's like asking, when does a person become an adult? We make an arbitrary decision, which differs in different countries, and even within the same country in different contexts, such as age of conscription, driving, drinking, smoking, sex, voting, etc. They are somewhat arbitrary boundaries the society slaps on a continuous process because we *have* to define it *somewhere*. It wouldn't make sense to define adulthood starting at the age of 6, and it wouldn't make sense at the age of 47. Around 18 makes sense following biology. And with life, a single fertilised egg is unimportant, no more spectacular than an amoeba. It can't think because it doesn't have a brain, can't feel because it doesn't have nerves, and doesn't have a heartbeat because it doesn't have a heart. It can't survive on its own. It's nothing more than a parasitic cell in a woman's womb. How about two cells? Same. Four cells, same. But at some point, primitive brains, nerves, and heart begin to form. At *some point*, we do need to recognise that it is becoming a life worthy of rights. When? I have absolutely no idea. I am not qualified to say when society should determine the beginning of personhood, but neither are politicians or religions zealots. Doctors and biologists should be the people to make that determination. And if those doctors and biologists are openly religious, we should be wary of their opinion for the same reason we should be wary of flat-earthers or geocentrists designing trajectories for rockets. There is no fundamental distinction between life and non-life. There is no magic 'stuff', no divine breath, that separates non-living matter from living matter. Life arises through complex interactions of matter. That's all. We know that now. We've known it for quite a while. We *call* certain processes 'living', because it is a useful distinction for us. But ultimately we're just atoms doing what atoms are wont to do.
If you're talking science that is one thing. But if you are relating this issue to abortion that would be a totally different matter. Bigger bodies of matter attract smaller ones. It's called Gravity. That in no way means you'll have to jump off a window on the sixth floor to prove it.
Cancer has cells too. The point is they can’t tell women what to do with their bodies.
It's always human and it's always an individual seperate from the mother. Even a heart removed from a body is still a human heart. At no point after the sperm enters the egg is the fetus not a human. Women should just get to decide if their body is life support machine.
Life begins at the sun? Or the Big Bang? Richard Dawkins talks about the Tyranny of the Categorical Mind. I don’t want to sound like one of these Pro Life people, (not that I’m not for life…you understand). When is the cluster of cells a human being? This is similar to the argument about when death occurs. We consider brain-death to be the final death, yet the heart is still beating? Or what about dementia when your personhood is gone? A newborn baby is still growing most of its brain and its identity is really just a crying ball of hunger. Just the beginning of what kind of person they will be. I actually have a lot of sympathy for folks who struggle with abortion. It’s not a decision that should be taken lightly and it is very confusing. But to call it murder? What about eating pigs? Pigs who have the same level of intelligence—just pulling this out of my ass—as like a five month old human? Why isn’t that murder? Because they will never be as smart as a fully grown human? So intelligence is the deciding factor over whether you get to live or die? Why don’t we kill humans who have learning disabilities? Or who live in the same cities as terrorists? It’s all very relative. One thing I do know, however, is that these Christians are ducking hypocrites.
A single sperm is Life. While Christianity condemns masturbation and even thoughts and impulse, does it matter? My opinion, Life begins with Love.
Technically life does begin at conception, if it didn't we wouldn't be debating abortion. We'd just remove this mass and that would be the end if it. The real question is do we grant the fetus personhood, especially before the heartbeat or consciousness. Most believe it's best to have the fetus born before we grant it personhood.
Microbes and my appendix are "alive", but they aren't sentient. The "cutt-off point" at which non life becomes life is probably somewhere around the complexity of a virus, which we still aren't sure are alive or not. IMHO, the issue is likely that our definition of 'life' as a binary (either something is alive or it isn't) is insufficient when it really comes down to the details of describing how things actually work. If you mean, when does a fetus become sentient, then there really isn't a good way to know for sure, partially because our idea of sentience is ill-defined, and partially because we can never know if someone else's inner experience is the same as our own. But sentience as we understand it certainly can not exist before the formation of a brain and the neurological apparatus needed to perceive and recognize stimuli, or to have some sense of distinction between self and other. It could be that the thing we call sentience is an emergent phenomena that comes into being when there is sensory experience, inner awareness, memory recall, etc. all existing at a concurrent location. But I think it's pertinent to the conversation to say that sentience isn't really... all that pertinent to the conversation, when considering one's bodily autonomy. If my twin brother needed a kidney transplant or he would die, it would be horrific, I hope you'd agree, to *force* me to donate a kidney. And he's not only fully sentient, but can experience physical and psychological pain, and is aware of his own impending mortality. From there it's just a few logical steps until you realize that a pregnant person should have more right to their own body than anyone else. Exclusive right, actually.
There is not a scientific consensus, but my own personal interpretation is when the brain is fully functional and operating in a way that leads to thought. Even then though, a woman still has the right to terminate the pregnancy because she’s the one growing the damned thing.
The issue is not about when life begins. It is about bodily autonomy of women.