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.

No. It depends on your standpoint on the status of a fetus. We are only charged with murder if we kill a human being. If a fetus is a human being, then it's murder. — Patterner

It doesn't depend on your standpoint on the status of a foetus. It depends on what the law says. If the law defines the crime of murder as including the killing of a foetus then killing a foetus is murder, and one is charged accordingly, otherwise it isn't and you won't be.

In both US federal and UK law, one can only murder those who have been born. This is the born alive rule.

I think consistency is important. — Patterner

Doing the right thing is more important, even if it appears "inconsistent".

I think we should be consistent. If it's murder then so is abortion. If abortion is not murder, then neither is this. — Patterner

Why?

There's an interesting question of the burden of proof here anyway. Do we have to prove that abortion is impermissible, in which case, lacking a proof, we can assume that abortion is permissible? Or do we have to prove that abortion is permissible, in which case, lacking a proof, we can assume that it is impermissible?

If we lack a proof both of the permissibility of abortion and of its impermissibility, can we just suspend judgement? I suppose we have to. In that case, there will be nothing to prevent people following their own consciences.

There is, at least at present, no conclusive argument available either way. In which case, there is no justification for a law either way and no ground to prevent people following their own consciences. — Ludwig V

Well, this is the issue I have with morality in general. I don't think any moral claims are either verifiable or falsifiable. Unlike science and maths there's just no way to prove or disprove one claim or another. We just either accept them or we don't, and then make our choices accordingly, and such choices include whether or not to pass a law to ban abortion.

I'm pro-choice.

You've left out a premiss. If deontology is true and the rules and principles are incompatible with abortion, then abortion will be impermissible. — Ludwig V

That's why I said "abortion may be morally impermissible". The point I was making is that @Samlw was assuming consequentialism in his defence of abortion. His defence fails if consequentialism is false, so to prove that abortion is permissible he must prove that its moral permissibility is determined by the consequences.

The last thing anyone should do is make a decision of this sort based on a philosophical theory — Ludwig V

Unless that philosophical theory is true. If deontology is correct and the moral permissibility of abortion is determined by rules and principles rather than by consequences then abortion may be morally impermissible even if the mother might suffer from not having an abortion.

You can say you are still preventing a human life and I agree, but the benefits out weigh the cons in my opinion. — Samlw

The counter claim is that either:

a) the benefits of an abortion do not outweigh the loss of a foetus' life, or
b) moral value is not determined by benefits, i.e. deontology is correct and consequentialism is incorrect

You are the one who claimed that it is acceptable kill a foetus if it is unconscious and unacceptable to kill a foetus if it is conscious. You must explain why being conscious matters. Asking me the question "why do we value human life over other life?" does not provide an explanation or a justification of your claim.

Why do we value human life over every other life? — Samlw

That question has no bearing on the pro-life claim that abortion is wrong. A pro-life advocate could equally be a vegan and believe that killing animals is wrong.

As it stands you haven't justified your claim that it is acceptable to kill an unconscious foetus.

I would say to that, your conscious, the foetus isn’t. So in some way you can’t use human rights in the argument because an abortion would be the same as killing something else that isn’t conscious such as a blade of grass. — Samlw

As I asked you before, why is consciousness the measure of the right to life?

Hanover offered the example of killing an unconscious person. I'll add to that the example of killing animals for food.

The matter isn't as simplistic as your reasoning would like it to be.

In my opinion that’s a weak counter because I can flip the same question and say, is it moral to take away the choice? — Samlw

It is moral to take away your choice to kill a foetus for the same reason that it is moral to take away your choice to kill me; both the foetus and I have a right to life, and our right to life takes precedence over your choice to kill us.

Around 60% of the world’s population has the right to an abortion. — Samlw

They have a legal right, sure, but the question is whether or not we have a moral right.

And in the interest of freedom and not allowing a government to have control on what life choices you want to make with your personal body, I would argue it should be a basic right. — Samlw

Do I have the basic (moral) right to kill you if you annoy me? Presumably you believe I don't. Some believe that I also don't have the basic (moral) right to kill a foetus.

So again you're just begging the question.

Additionally, it's seen as a road to euthanasia of the elderly, sick, or infirmed, which is in the same territory as readily-available state-sanctioned/assisted suicide if someone happens to convince themself (or, and this is the concern, becomes convinced by others) they should cease living, even for reasons as minimal and transient as a break-up, divorce, or loss of a job or having a bad year, month, week, or even day. — Outlander

Well that's a slippery slope fallacy.

But this also brings me back to my first point. This is a belief, and to take away rights from people simply because of that I find disgusting. — Samlw

You've begged the question by assuming that we have the right to an abortion.

I understand where people would get that from, however my counter would be that it would be wrong to kill a foetus that is conscious, I think the logic of every foetus is a potential life is correct however, to call it murder would be dramatic aslong as the foetus isn’t conscious. — Samlw

Why is consciousness the measure of the right to life?

I have never heard a compelling argument for pro-life. All of them have been based on religion or personal feelings in which my answer is always to simply not have an abortion. — Samlw

Well, we could start with perhaps a premise that we all agree with:

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.

To rebut it one might have to argue either that P2 is false or that there is some n such that "it is wrong to kill a baby n days before birth" is true but "it is wrong to kill a baby n + 1 days before birth" is false.

The fact that abortions are legal doesn't force you to do anything, you can choose to have the child. My main issue with pro-life is that your taking away a choice for people that don't share the same beliefs when having it the other way, everyone can do what they want. — Samlw

They believe that abortion is murder. Telling them that abortion should be a choice is, to them, telling them that murder should be a choice. Most of us don’t believe that murder should be a choice.

I don't quite get the problem. Let's say that there's something hiding under my bed cover. I cannot see under my cover to see what it is; I can only see the bump in the cover (and maybe the cover moving). Any knowledge I have of the thing under my cover is at best an inference.

It's the same principle with things like Kant's transcendental idealism or indirect realism.

And then on the further extreme the idealist claims that there isn't anything under my cover; there's only the cover, which happens to have a bump (and maybe is moving).

So at least we agree with the principle that some speech shouldn't be allowed. The difficulty is in deciding exactly which speech shouldn't be allowed.

On the other hand it seems reasonable to punish people for knowingly false bomb threats.

Are you suggesting that slander and bomb threats shouldn’t be illegal?

But why? — NOS4A2

Why is slander illegal? Why are bomb threats illegal? We criminalise certain speech because we believe that allowing them would do more harm than good.

Only when it violates criminal code, like with slander and so on, there should be penalties.

And presumably the suggestion is that the criminal code should include such things as misinformation along with slander and so on.

Yet part of what confuses these threads is that there really are colored objects outside the body, in the sense that there are really objects which reflect light in ways that allow them to be discriminated. — hypericin

If by "coloured objects" you just mean "objects which reflect light which cause colour sensations" then sure. But that's dispositionalism, not naive colour realism.

Moreover they really do look the way they do: appearing this way (to humans) is a stable, mind independent property (just not independent of all minds, it is like a social reality) — hypericin

Yes, and stubbing one's toe really is painful. But pain is still a sensation.

I think of sensations as events in the body, but colored object appear outside of it. — NOS4A2

And this is where you're making a mistake. Visual sensations are events in the body (specifically events in the visual cortex). Depth is a characteristic of visual sensations, and so it seems as if there are coloured objects outside the body. But this is as misleading as phantom limbs.

You appear to be under the impression that visual perception is fundamentally different to other modes of perception, such as pain, smell, and taste. It really isn't. Each perceptual system simply involves different organs responding to different stimuli eliciting different types of sensations.

I don’t think believing what one is told or accepting an argument from authority is particularly rational — NOS4A2

Believing what scientists say about what their scientific studies have determined about the world (including perception) is rational. It is rational to believe in the Big Bang, evolution, atoms, electromagnetism, superposition, and so on, even if any of it conflicts with "common sense", and even if one hasn't carried out the experiments oneself.

Why would we need to change the properties of the object if color is not a property of the object? — NOS4A2

We need to change how the object reflects light because the wavelength of the light that stimulates the eyes is what determines the type of colour sensation elicited.

Pain is a sensation, it hurts to put my hand in very hot water, I add cold water to reduce the temperature, and so I no longer feel pain when I put my hand in.

Besides, sensations aren’t red any more than the word “red” is. Sensations or experiences do not have any properties to begin with. If we are to abandon common sense and the world for pseudo-objects and things without properties we're going to need much more than that. — NOS4A2

I don't understand what you're trying to say here. Do you accept that pain is a sensation? Do you accept that a bitter taste is a sensation? I am simply pointing out that colour is another type of sensation, specifically a visual sensation. This may not be "common sense", but common sense does not determine the facts, and in this case common sense conflicts with the scientific evidence. I trust the scientific evidence.

If you want to reject the scientific evidence in favour of common sense then go ahead, but it's the less rational position to take.

What we do with paints, phosphors, pigments, suggest that the color is out there among the surfaces of the objects these adjectives are meant to describe. — NOS4A2

We just use those things to change the way an object’s surface reflects light. That does not suggest that colour is a mind-independent property of the object’s surface.

Perhaps you could explain which (if any) of these you believe:

1. “the apple is red” means “the apple reflects ~700nm light”
2. The apple is red because it reflects ~700nm light
3. The apple reflects ~700nm light because it is red

On the other hand, there is no indication color sensations exist. — NOS4A2

Yes there is. Dreams, hallucinations, variations in colour perception (e.g. the dress), and studies such as this. This is why James Clerk Maxwell in On Colour Vision (1871) said "it seems almost a truism to say that color is a sensation".

And as the SEP article on colour explains:

One of the major problems with color has to do with fitting what we seem to know about colors into what science (not only physics but the science of color vision) tells us about physical bodies and their qualities. It is this problem that historically has led the major physicists who have thought about color, to hold the view that physical objects do not actually have the colors we ordinarily and naturally take objects to possess.

It would be helpful if colour realists explain which of these they believe:

1. “the apple is red” means “the apple reflects ~700nm light”
2. The apple is red because it reflects ~700nm light
3. The apple reflects ~700nm light because it is red

colored objects occur outside the body in a space independent of the mind. — NOS4A2

Objects outside the body just reflect different wavelengths of light. This light causes one type of colour sensation in humans and another type of colour sensation in dogs.

Color is a fiction. — NOS4A2

No it’s not, it just isn't what you claim it to be.

I don't see how it is useful to distort the picture with a fiction. — NOS4A2

Your reasoning is akin to arguing that because pain is not a mind-independent property of fire then it is not useful and a distortion and a fiction to feel pain when we put our hands in the fire.

The eagle has 20/5 eyesight, more rods and cones, and see much better. According to color factionalism they invent color, too, and somehow paint the images with their brain, but why would animals with such great sight distort their sight with color? — NOS4A2

It's clearly useful to visually distinguish objects which reflect 400nm light and objects which reflect 700nm light. Colour sensations is how we do that.

Take this for example:



It's not that either humans or dogs (or neither) is seeing the "correct" (mind-independent) colour when looking at an object that reflects 500nm light; it's just the case that 500nm light causes different colour sensations for humans and dogs.