My own take is that for the most part essentialism is false. There's no such thing as the essence of personhood; there's just the social fact that we use the word "person" to refer to certain types of organisms and not to others, based on some general characteristics (much like the word "game").

It happens to be the case that the general characteristics that prompt our use of the word "person" also also happen to be the general characteristics that 'grant' the appropriate moral rights.

So it's not exactly the case that we ought not kill someone because they are a person, but that someone is a person and we ought not kill them because they have thoughts and feelings and wants and so on.

Saying "we ought not kill him because he's a person" is just a more succinct phrasing.

it seems pretty clear that what's being done is recasting the indirect realist in a way that it can be subsumed under an extended version of 'direct realism'. — AmadeusD

Yes, something like this is argued in Semantic Direct Realism that I often quote. There's phenomenological direct realism, or naive realism, that indirect realism opposes (consistent with the scientific evidence), and then there's semantic direct realism which agrees with the indirect realist's rejection of naive realism but calls itself direct realism anyway.

I see something like that here as well, where some accept the existence of mental representations but still call it direct realism even though representationalism is indirect realism.

I think part of the problem is that some here think that "I see a tree" and "I directly see a tree" mean the same thing, when in fact the adverb "directly" modifies the verb "see".

I considered that part irrelevant, insofar as we know nothing of a thing by its effect on our senses, except that is “…an undetermined something….”. To say we know how they affect our senses is already given by sensation, which only informs as to which sense it is, but nothing whatsoever about the thing, except its real existence. — Mww

I don't understand what you're trying to say here.

It is not a contradiction to say that the only thing we know about the magnetic field is how it affects the behaviour of metal (although it may be false).

And it is not a contradiction to say that the only thing we know about distal objects is how they affect our sensory experience (although it may be false).

Yes, it is wrong to intentionally kill a fetus for the same reasons it is wrong to kill any other human being. — NOS4A2

What are these "same reasons"?

Because I would say that it is wrong to kill other humans because it is wrong to kill humans with thoughts and feelings and wants. Embryos and (early stage) foetuses don't have thoughts or feelings or wants. They are more like the brain dead living on life support.

You can disagree with the premise that a fetus is a human being, or that it is not wrong to kill human beings, but it’s difficult to reasonably do so. — NOS4A2

It's not difficult when you make sure not to equivocate. See my post above.

What if the mother wants the child. Does the zygote then deserve a chance at life and become worthy of protection.. — NOS4A2

Only to the extent that the mother deserves her wants respected.

What biological differences make it not wrong to kill and embryo, but wrong to kill a baby? — NOS4A2

The biggest and most relevant difference is that a baby is no longer being carried in the womb of its mother, and so the mother's bodily rights are no longer an issue.

Another significant difference is that the thalamocortical connections that are required for consciousness do not develop until ~26 weeks of pregnancy.

I’ve already described my reasoning and the entities it applies to as best as possible. — NOS4A2

You've asserted that it is wrong to kill anything with human DNA (except in self-defence, etc.). You haven't shown what makes it wrong.

The baby was an embryo. — NOS4A2

It was an embryo, but now isn't. There is a very real biological difference between a baby and an embryo. This very real biological difference has moral relevance and is why it is wrong to kill a baby but not wrong to kill an embryo.

I would refrain as best as possible from positing phantom properties and folk biology. — NOS4A2

So are you now saying that it isn't wrong to kill a human embryo? Or are you refusing to show me what makes killing a human embryo wrong? This is why you are special pleading; you demand that we show you what makes something a person but refusing to show us what makes killing a human embryo wrong.

If I ask you to show me what makes it a person... — NOS4A2

And if I ask you to show me what makes killing a human embryo wrong?

If you’re going to condemn some human beings to death because you’ve relegated them to the status of non-person, you better have something better than your own thoughts and feelings. — NOS4A2

There is a very real biological difference between an embryo and a baby. They might share the same kind of DNA, but there is much more to an organism than its DNA.

I think it's important to avoid any equivocation.

This seems to be the pro-life argument:

a) "X is a human" means "X has human DNA"
b) It is never acceptable to kill a human
c) Therefore, it is never acceptable to kill something with human DNA

The pro-choice crowd deny that both (a) and (b) are true together; it's one or the other:

a) "X is a human" means "X has human DNA"
d) It is sometimes acceptable to kill something with human DNA
e) Therefore, it is sometimes acceptable to kill a human

or

b) It is never acceptable to kill a human
d) It is sometimes acceptable to kill something with human DNA
e) Therefore, "X is a human" does not mean "X has human DNA"

I don’t understand why I need to point to a property of “wrongness”. I also never said someone needs to point to a measurable property of being a person. I was saying there is no such measurable property, so it makes zero sense that I would say you need to point to one. — NOS4A2

Echarmion asked "is this supposed to mean that there's no evidence for personhood?"

You responded with "I understand, and have no problem with either term in common usage, but if I were to ask you to point to whatever it is you're referring to you would invariably point to your body, which has existed and grown since conception. That's what I'm hung up on."

I am simply explaining that being (or not being) able to point to something has no bearing on whether or not someone is a person, just as being (or not being) able to point to something has no bearing on whether or not something is wrong.

My argument this whole time is that it’s wrong to intentionally kill a human being (unless he deserves it or it is in self-defense), to deprive him of life. A fetus is a human being. — NOS4A2

And this is where there is disagreement. It is wrong to intentionally kill a born human, and perhaps a foetus of a sufficient age, but it is not wrong to intentionally kill an embryo or young foetus.

The possession of human DNA and the future possibility of being born is not sufficient grounds to force a pregnant woman to carry the child to term.

If not-A entails (B and (not-B)), then A is entailed. Is that what you're saying isn't the case?
Is B here the proposition that the universe has an nth term? And A is the proposition that there's a non-contingent entity in the universe's series of terms? — Hallucinogen

The example of the Presidents explains what I mean in simple terms.

You conflate "A is required for B" and "A is necessary". The former does not entail the latter.

given that all non-contingent entities are necessarily omnipotent and eternal — Hallucinogen

That's not a given.

To deny theism is to deny a necessary entity — Hallucinogen

One can believe in some necessary thing without believing that this thing is God. Theism does not have exclusive ownership of necessity.

Perhaps the necessary entity is a physical singularity of infinite density that underwent a rapid expansion known as the Big Bang. The atheist can accept this.

….but only know its appearance…..no. The thing-in-itself does not appear; if it did, it wouldn’t be in-itself. It would be that object of sense as mere appearance, hence the contradiction. — Mww

You should read the next part:

viz., the way in which our senses are affected by this unknown something.

i.e. the only thing we know about distal objects is how they affect our senses.

"B and if not A then not B" does not entail "necessarily A".

B ∧ (¬A → ¬B) ⊭ □A

As an example, a 46th President of the United States requires a 1st President of the United States, but a 1st President of the United States is not necessary.

Regarding Kant's ding an sich, I think this quote provides a simple account of it:

And we indeed, rightly considering objects of sense as mere appearances, confess thereby that they are based upon a thing in itself, though we know not this thing as it is in itself, but only know its appearances, viz., the way in which our senses are affected by this unknown something.

As an analogy to this that the direct realist can accept; we do not see magnetic fields, only the affects that magnetic fields have on other things such as metal.

Kant (and other indirect realists) simply apply this same reasoning, arguing that metal is to phenomenal experience as the magnetic field is to metal (except, at least with respect to sight, there is not even direct physical contact between metal and the sense organ).

Of course, we are able to formulate mathematical models of this magnetic field, use these models to try to predict observable phenomena, either falsify or fail to falsify our models, and in doing so can be said to "know" something of the "thing in itself", but I'm not sure if this sense of knowing the thing in itself is the sense that is relevant to Kant's remarks above.

But then even if scientific realism is inconsistent with transcendental idealism, one can be an indirect realist and a scientific realist, so if this discussion is trying to equate indirect realism with transcendental idealism and argue that any problems with the latter are also problems with the former then I think it commits a fallacy. Much like the scientific realist, an indirect realist can accept that we can know something about things that we cannot directly perceive.

There’s a world, it’s really a world…..so what? World being, of course, an abstract entity. Sorta like Rawls (?)….where’s the university.
(Crap. I can't remember the author or the name of the paradox. Maybe identity. Guy sees all the accoutrements which constitute a university, but wants to know where the university he came to visit is located.) — Mww

Gilbert Ryle's category mistake from The Concept of Mind.

Funny, innit. An ordinary folk looks out, is perfectly convinced he sees a tree, but you the metaphysician tell him, nahhhh, you don’t. You see a thing, and that thing is only called a tree because somebody, somewhere, some long time ago, said so, and you’re just regurtitatin’ what’s been taught to you.

But then, there’s markedly more ordinary folk than there are metaphysicians, so…..there ya go. “I see a tree” rules the day. — Mww

A relevant passage from here:

Here is a kind of puzzle or paradox that several philosophers have stressed. On the one hand, existence questions seem hard. The philosophical question of whether there are abstract entities does not seem to admit of an easy or trivial answer. At the same time, there seem to be trivial arguments settling questions like this in the affirmative. Consider for instance the arguments, “2+2=4. So there is a number which, when added to 2, yields 4. This something is a number. So there are numbers”, and “Fido is a dog. So Fido has the property of being a dog. So there are properties.” How should one resolve this paradox? One response is: adopt fictionalism. The idea would be that in the philosophy room we do not speak fictionally, but ordinarily we do. So in the philosophy room, the question of the existence of abstract entities is hard; outside it, the question is easy. When, ordinarily, a speaker utters a sentence that semantically expresses a proposition that entails that there are numbers, what she says is accurate so long as according to the relevant fiction, there are numbers. But when she utters the same sentence in the philosophy room, she speaks literally and then what she asserts is something highly non-trivial.

You’re making nouns out of my adjectives. I don’t believe wrongness and rightness and rights are measurable properties of anything. — NOS4A2

So you claim that killing foetuses is wrong but don't need to point to some measurable property of being wrong because "wrong" is an adjective, and others claim that foetuses aren't people and need to point to some measurable property of being a person because "person" is a noun?

Such an argument from grammar is special pleading.

There needs to be some basis for granting rights in the first place. — NOS4A2

That doesn't really address the question. According to your own account of rights there's nothing more to rights than someone having said something like "so-and-so has the right to such-and-such".

So John says "foetuses have a right to life" and Jane says "foetuses don't have a right to life". Where do we go from here?

Do you want to argue that one of John and Jane is correct and the other incorrect? Then there's more to rights than someone having said something like "so-and-so has the right to such-and-such". And so, using your own reasoning, one must be able to point to some measurable property which is "the right" (independent of what either John or Jane say). Can you do that?

But then you also say above that it's not about rights but about wrongness and deservingness, which just shifts the problem: using your own reasoning, one must be able to point to some measurable property which is "wrongness" and "deservingness". Can you do that?

Or perhaps you simply need to accept that not everything is a measurable property that can be pointed to, whether that be "right", "deservingness", or "personhood".

I wasn’t necessarily speaking about rights. I was saying they deserve a chance to live and that it is wrong to kill them. — NOS4A2

I mean you said this:

Our bodies have largely evolved for the task of protecting human life in its earliest development, and many of us hold to right-to-life principles, for instance that a human being in its earliest development deserves a chance to live.

So forgive me for being confused.

Are you now suggesting that it can be wrong to kill a foetus and that a foetus deserves the chance to live even if they haven't been granted the right to live?

"Life begins at conception" is an imprecise short-hand for "a human life begins at conception". Stop picking the low hanging fruits: obviously a sperm is alive and so is my skin cells---we are talking about when a human being is alive. — Bob Ross

I was just explaining what Echarmion was saying. I understood you as misinterpreting him as saying that life begins after conception. Maybe I misunderstood you.

Einstein? The more you post the more evangelistic your approach becomes. This is a site for philosophical argument. Evangelism is literally against the rules. — Leontiskos

My claim is that the scientific evidence shows that naive realism is wrong, and I support this claim by referring to experts in the field, such as Einstein, who best know what the scientific evidence shows.

Are you claiming that Einstein and I are wrong in claiming that the scientific evidence shows that naive realism is wrong, or are you claiming that the scientific evidence itself is wrong?

??? . I can't tell if you are joking. — Bob Ross

I'm not. A sperm cell is a single-celled organism. It's alive.

It is an undisputed scientific fact that life begins at conception: it is the clear beginning mark of the ever-continual development cycle of an individual human being (until death). — Bob Ross

I believe the point he was making is that sperm cells are alive, and so that life began before conception.

Human beings have no rights other than those that have been declared and conferred by others. — NOS4A2

So a foetus doesn’t have a right to live unless some authority declares and confers that right?

Then what exactly are you trying to argue here? Because with the above in mind all we can do is describe the fact that in some places and at some times abortion is legal and in other places and at other times it is illegal.

No measurable property called “personhood” appears or disappears in any given human being — NOS4A2

Most of us are quite capable of understanding what “person” means, that rocks, embryos, and flies are not people, and that adult humans (and intelligent aliens) are people. The type of “personhood” that you think doesn’t exist isn’t the type of personhood that any of us are talking about.

So what grounds are there to make the distinction now? — NOS4A2

The very real and obvious observable differences between rocks, embryos, and flies on the one hand and born humans on the other hand.

The fact that an embryo has roughly the same DNA as me and will eventually grow into an organism like me simply isn’t sufficient grounds to grant it the same rights as me or even just the right to live at the expense of the rights of the woman who must carry it to term.

That’s one of their manifestations, sure. Grab any bill of rights and point to a right, you’ll have your answer in what it consists of. If there is more to it, go ahead and reveal it. — NOS4A2

That's not a right. That's a supposed description of a right. The words are not the thing they describe. I'm not asking you to point to words that describe a right; I'm asking you to point to a right.

As it stands it amounts to me pointing to the word "person" and saying that I'm pointing to a person.

It’s wrong to kill a fetus for the same reason it is wrong to murder a 40 year old. Both are deprived of a future against their will. Both have their bodies destroyed against their will. The world and the community are deprived of their presence against their will. In any case, any evidence or reasoning to support the claim that it is wrong to kill a 40 year old can be applied to any other human being in any other stage of its life, including early development. — NOS4A2

Killing a 40 year old isn't wrong just because "he is deprived of a future against his will". It's wrong because "he is deprived of a future against his will and is a person". The "and he is a person" has moral relevance. It is not wrong to deprive a foetus of its future against its will because a) it's not a person, and b) it doesn't even have a will.

Can I grow fetuses in order to harvest their organs and sell them, in your view? Why or why not? — NOS4A2

You mean like scientists growing ‘mini-organs’ from cells shed by foetuses or cultivating embryonic stem cells in general?

Yes, that's acceptable. It could save many lives.

Relevant paper on that last point:

Could Artificial Wombs End the Abortion Debate?

One should distinguish two aspects of abortion that are currently but not necessarily linked—extraction and termination. Abortion rights might be understood as the right not to be pregnant, the right not to have the human fetus in the womb, the right of extraction. On the other hand, abortion rights might be defined as the right to end the life of the human fetus in utero, the right to terminate not just the pregnancy, but also the life of the fetus. These two understandings of abortion, although distinct, are at least for the present linked, since one cannot currently accomplish evacuation of the human fetus from the uterus at an early stage of pregnancy without also terminating the life of the human fetus. Accordingly, one could advocate the right of evacuation or extraction, that is, the right to have the fetus removed from the woman’s body, and yet not advocate a right of termination, that is, the right to have the fetus killed within the woman’s body.

You can point to a right if you write it down. — NOS4A2

So a right is a piece of paper with ink markings? That doesn't seem right.

To do so to a fetus would deprive it of the chance to ever do so. — NOS4A2

And that's the point of departure. It is argued that it is not wrong to deprive a foetus (or embryo) of the chance to become a person; or that there is insufficient evidence or reasoning to support the claim that it is wrong; or that it is more wrong to force a woman to carry the foetus (or embryo) to term.

Perhaps abortion would be wrong if embryos and foetuses were grown in some artificial womb, but the fact that they grow inside a person with rights of their own is a fact that has moral relevance.

@NOS4A2

I should add that I'm also somewhat perplexed by your questioning of personhood but your acceptance of rights. Can you point to rights? If not then why expect someone to be able to point to personhood as if not being able to is a gotcha?

Some things just can't be pointed to.

I understand, and have no problem with either term in common usage, but if I were to ask you to point to whatever it is you're referring to you would invariably point to your body, which has existed and grown since conception. That's what I'm hung up on. — NOS4A2

Think of the difference between a wave and still water. All waves are water but not all water is a wave. The body (specifically the brain) has to be doing something for there to be a person. If the brain isn't doing that thing then there is no person, which is why neither a corpse nor an embryo is a person.

But one of the challenges the pro-choice advocate faces is explaining the dividing line between killable and not-killable. When and how does that transition take place? — frank

It's gradual.

Let's take the pro-life argument I offered at the start:

P1. It is wrong to kill a baby the day after birth.

The argument would then be:

P2. If it is wrong to kill a baby the day after birth then it is wrong to kill a baby the day before birth.
C1. Therefore, it is wrong to kill a baby the day before birth.
P3. If it is wrong to kill a baby the day before birth then it is wrong to kill a baby two days before birth.
C2. Therefore, it is wrong to kill a baby two days before birth.
...
etc.

This line of reasoning will entail the conclusion that it is wrong to kill a baby from the moment of conception. — Michael

The counter argument is:

P1. It is wrong to kill a baby the day after birth.
P2. It is slightly less wrong to kill a baby the day before birth than the day after birth.
P3. It is slightly less wrong to kill a baby two days before birth than the day before birth.
P4. It is slightly less wrong to kill a baby three days before birth than two days before birth.
...

At some point any degree of wrongness, if there is indeed any wrongness left, is insignificant compared to the wrongness of not allowing a woman to terminate her pregnancy.

It's much like the Sorites paradox. We might not be able to determine where the line is drawn, and there might not even be a precise point where some line is drawn, but we can say at the one extreme a single grain of sand is not a heap and a newly conceived embryo does not have an overriding right to life, and at the other extreme 1,000,000 grains of sand is a heap and a three year old child does have an overriding right to life.

All of them involve the intentional killing of very young and helpless human beings. That’s all I mean. — NOS4A2

But not all of them involve killing an embryo or foetus. That is a significant moral difference.

Abortion rights is often posited as a mark of an enlightened society, when in fact infanticide, child sacrifice, and acts of these sorts is a stone age and barbaric practice. — NOS4A2

Abortion is nothing like infanticide or child sacrifice.

And of course this tired claim has been shown to be unsupportable any number of times in the recent thread — Leontiskos

Let's take the words of Albert Einstein as an example:

This more aristocratic illusion concerning the unlimited penetrative power of thought has as its counterpart the more plebeian illusion of naive realism, according to which things "are" as they are perceived by us through our senses. This illusion dominates the daily life of men and of animals; it is also the point of departure in all of the sciences, especially of the natural sciences.

If you want to argue that naive realism is correct then fine, but it's clearly the unscientific view. The findings of physics, neuroscience, and psychology are firmly opposed to it, despite your insistence otherwise.

and the vast majority of people are naive realists — Bob Ross

Maybe laymen and philosophers, but that's not the view of those who study perception scientifically.

Take Perception#Process_and_terminology for example:

The process of perception begins with an object in the real world, known as the distal stimulus or distal object. By means of light, sound, or another physical process, the object stimulates the body's sensory organs. These sensory organs transform the input energy into neural activity—a process called transduction. This raw pattern of neural activity is called the proximal stimulus. These neural signals are then transmitted to the brain and processed. The resulting mental re-creation of the distal stimulus is the percept.

To explain the process of perception, an example could be an ordinary shoe. The shoe itself is the distal stimulus. When light from the shoe enters a person's eye and stimulates the retina, that stimulation is the proximal stimulus. The image of the shoe reconstructed by the brain of the person is the percept. Another example could be a ringing telephone. The ringing of the phone is the distal stimulus. The sound stimulating a person's auditory receptors is the proximal stimulus. The brain's interpretation of this as the "ringing of a telephone" is the percept.

The different kinds of sensation (such as warmth, sound, and taste) are called sensory modalities or stimulus modalities.

And also this:

Indirect realism is broadly equivalent to the scientific view of perception that subjects do not experience the external world as it really is, but perceive it through the lens of a conceptual framework. Furthermore, indirect realism is a core tenet of the cognitivism paradigm in psychology and cognitive science.

Whatever "rational" grounds you might have for believing in naive realism, it is incompatible with physics, biology, neuroscience, and psychology.

I don't understand what you're trying to argue here.

I am simply explaining that we very often, both in particle physics and everyday life, observe one thing to happen and then use that thing to infer the existence and behaviour of something else.

The direct scientific realist believes that such things as dark matter, gamma radiation, and electrons cannot be perceived directly, and can only be inferred by the effects that they have on the things that can be perceived directly.

The indirect realist believes the same thing, but just adds things like apples and chairs to the list of things that cannot be perceived directly.

It's the same reasoning for everyone, they just disagree on where the line is drawn. Is it at the mental/neurological/biological, or further beyond the body?

Even the direct realist (if also a scientific realist) can believe in the existence of things that he cannot directly perceive (e.g. electrons and dark matter), and believe that these things are very unlike the things that he can directly perceive.

Whereas the direct scientific realist believes that his direct perception of a Geiger counter gives him reason to believe in the existence of radiation, the indirect realist believes that his direct perception of qualia/sense data/whatever gives him reason to believe in the existence of a Geiger counter.

Your reasoning as it stands applies to believing in anything that one cannot directly perceive, and so would call into question almost all of science (especially particle physics).

Or referring back to my original example, your reasoning would entail that it is irrational to believe that there is something moving under my bed covers.

Are you willing to commit to this?

The problem is that you have hidden the paradox, but it is there in your example. Either you trust the evidence you are using to infer whether or not there is such a thing under your bed, and what it is, or you do not. If you do, then you are trusting that evidence to give you accurate information about the "under the bed as it is in-itself": if you deny that have any such trustworthy evidence, then you have not reason to believe you can infer, other than blindly and absurdly, what is under there. — Bob Ross

I am able to believe that there is something under my covers without looking under my covers. I use what I can see to infer the existence of something that I cannot see. This is not a paradox or a contradiction or any sort of logical fallacy.

For a species to intentionally kill its own fetuses is exceedingly unnatural. — Leontiskos

Lots of things we do are “unnatural”. But then also killing one’s offspring happens in nature too. There are various species of birds that occasionally kill the weakest baby so that they can better feed the others.

Regardless, I’m not sure what “naturalness” has to do with morality.

If moral realism is correct, then there is. — Ludwig V

Moral realism can be true even if moral truths cannot be determined.