Because you won't I suspect it is also useless to reply - but we'll give it a try: travelers moving apart will each seem to the other to be getting smaller, and each will measure the other's clock as running slower. Part of the clock's being measured as running slower is Doppler effect, and part the effects of relativity. There's obviously no accounting for what a person might conclude from this, and relativity on that provides no guidance. — tim wood

Again: explain how the twin example provides support for relativism about time. You have yet to do so. That is, show me that you are not guilty of the rank stupidity of the person who reasons that the twins are both getting smaller than each other.

You also assume I am not educated on these matters. Okay, well, this is a philosophy forum - so let's see how well educated you are on the philosophy of time. Just for starters, have you read McTaggart's famous paper? (There will be follow-up questions).

You either know what you mean and can make it clear, or you don't and cannot. — tim wood

I think I've been very clear. I want to know how the twin case is supposed to provide us with evidence that time is relative. For it seems to me that most of those who reason about these sorts of case commit egregious fallacies.

So, again, here is my parallel example, one that illustrates, very clearly, just how stupidly people are reasoning about the original twin case.

My twin is travelling away from me. From my perspective he appears to be getting smaller. From his perspective, I appear to be getting smaller. Conclusion Tim Wood would draw: therefore both of us are actually getting smaller than each other.

As for what I understand relativity to mean in this context: well, someone who held that time was relative would deny that there is an absolute now. That is, there is no 'now', there is just 'now-for-x'.

(A) If someone's a given sex when and only when they have most of the sexual characteristics associated with that sex, then we can't change sexes through surgery and medicine at the minute. — fdrake

The word 'can' is ambiguous. I was talking about what is metaphysically possible, not what is medically possible. If sex is constitutively determined by physical features, then it can in principle be changed because we do not have any of our physical attributes essentially.

We can, of course, distinguish between physical attributes we know how to change and those we do not. If sex is constitutively determined by physical attributes we know how to change, then it is medically possible for us to change a person's sex, whereas if sex is constitutively determined by physical attributes some of which we do not know how to change, then it is not medically possible for us to change a person's sex.

But I strongly suspect that most of those who think it is not medically possible for a person to change sex actually hold that changing sex is something that could not be changed no matter what physical changes a person underwent. For upon reflection it simply seems implausible that someone who refused the status 'woman' to someone who had acquired boobs and a vagina would then happily grant it if that person took a chromosomal-structure-change-pill. Some might, of course. But I think most wouldn't - they'd just change their position, searching for some yet more demanding set of criteria for qualifying as one sex rather than another. (For an analogy, in debates over capital punishment many oppose it ostensibly on the grounds that it is not an effective deterrent; yet when asked to imagine that it is as effective a deterrent as lengthy imprisonment most of them agree that they would still be morally opposed to it under those circumstances, showing that their 'real' concern about it lay elsewhere).

Their actual position - most of them, anyway - is that sex has a historical aspect to it, and thus to qualify as one sex rather than another it is important not just what properties you currently have, but either/or what properties you were born with, or how you acquired them.

Such views are, I think, not particularly plausible. No more so than the chromosomal view. But perhaps most importantly, these views are especially implausible when it comes to those issues that divide people.

So, let's just grant - purely for the sake of argument - that to be a woman you need to have a certain bundle of properties and also to have acquired them via a 'natural' process. Whereas someone who has all the same physical characteristics as a woman but has not acquired them 'naturally' is a 'woman', not a woman. Well, it isn't remotely plausible that the woman should be permitted access to female toilets and the 'woman' not. And it isn't remotely plausible that the woman should benefit from positive discrimination policies designed to ameliorate prejudice and the 'woman' should not. And it isn't remotely plausible that it is ok to insist on calling the 'woman' a man, when doing so is likely to make that person feel very uncomfortable (for an analogy, that would be akin to insisting on calling adoptive parents 'not real parents' whenever they refer to themselves as parents. Imagine a parent's evening at a school where the teachers insist on seeing parents who've adopted separately from all the rest, because 'they're not real parents').

And that's 'if' these demanding views of sex qualification are correct - which they're likely not.

I think most of those who claim sex can't be changed will change their mind if a pill is created that in every way changes one's sex. — Hanover

What you've said isn't quite what I said.

Whether chromosomal change is or is not necessary for sex change to have occurred is partly what's under debate (I am sceptical that it is). For instance, if one holds that sex has a historical aspect to it, then there would be no pill capable of "in every way" changing one's sex.

My prediction was that if a pill was developed that would overnight change your chromosomal structure, most of those who would deny sex has been changed by the acquisition of boobs and a vagina would continue denying that sex has been changed. There will be exceptions here and there - and it is just a prediction - but I think it is true.

You exaggerate your opponent's position to suggest most of them are arguing that sex is metaphysically immutable. — Hanover

I don't think it is an exaggeration. There are some who hold such views here, so we can simply see if they deny it.

A clownfish changes gender over its life as do other reef fish after all. — Hanover

They would point out that their change is 'natural' and not a product of human intervention. Again, they would cite historical properties and insist that what matters is not what properties you've acquired, but how you acquired them.

There is validity to the argument that a man cannot be made the same as a biologically born woman as a matter of current scientific fact. The immutability of gender argument you've attacked appears to attack a strawman, or at least a very very minority held position. — Hanover

No, these matters are not determined scientifically. There are some physical attributes, including chromosomal structure, which (I expect) we do not know how to change, but they're still capable of being changed, it is just we don't know how.

Is a trans woman and a cis woman the same to me? No, not really. One has female genes and female genitalia and the other male genes and no genitalia. That is just the truth. I'd change my mind if the pill you described were created though. — Hanover

I think many of those who would deny that someone who was born a man but now has boobs and a vagina is a woman, would continue to make that denial if that person then took that pill. For what would irk them is that this person was not 'always' this way.

You don't get it - the twin paradox in no way implies the relativity of time.

ah, so you don't really know what you're on about.

Is your book written in crayon?

right. So we can't conclude anything about the nature of time from the example. All the example illustrates is that two people can acquire equally justified contradictory beliefs about something. Which is something every thoughtful person already knew.

I really am justified in believing my twin is getting smaller as he moves away from me, and he really is justified in believing the opposite. From this we can no more conclude that size is relative than that it is absolute. The same, I take it you would agree, applies to time.

er, no. You - you- keep affirming the consequent. I have not. My arguments are all valid.

You are just reasoning fallaciously.

This is valid:

1. If p, then q
2. P
3. Therefore q

This (how you are reasoning) is not:

1. If p, then q
2. Q
3. Therefore p.

but again, you seem to be confusing epistemological possibilities with metaphysical ones.

Two people can be equally justified in believing contradictory propositions - and there can be nothing we can do to confirm which belief, if either, is true. But you can't conclude from that that both are true. Yet that seems exactly what you would need to do to derive any substantial conclusion about time from the twins paradox.

So this is not a point about reality, or time, but about justified beliefs, yes?

When my twin travels away from me, it seems to me that he is getting smaller and smaller than me. And from his perspective, as he travels away from me, I seem to be getting smaller and smaller than him.

Now, what do we conclude? That we are both getting smaller than each other? No, that's clearly impossible. And it remains impossible even if, due to the fact we've both travelling away from each other, we'll never meet to be able to compare body sizes.

We are not both getting smaller than each other - because that's impossible as a moment's reflection reveals - and that remains true even if, due to our impressions of what's happening, we're both equally justified in believing that we are getting smaller than each other.

Two people can be equally justified in holding contradictory beliefs - there's no problem with that. What is problematic is holding that something contradictory is actually true.

Two people cannot both be older than each other. Two people cannot both be smaller than each other. But two people most certainly can believe that they are older than each other, and be equally justified in that belief; and two people can be equally justified in believing that they are smaller than the other.

So, again, how do you conclude anything about time without committing yourself - on pain of inconsistency - to holding that time travels slower in fridges?

But we (all creatures great and small) have a stable and, for all practical purposes, an unchanging identity. This is a good thing, again in my opinion. A creature can fulfill the role for which it is suited. Some creatures can fulfill several roles. An ox can be a source of meat, and a source of traction. An ox can not breed, however, because oxen are sterilized male cattle.

What a man can do is take the role of a woman; visa versa for a woman. There may be satisfactions in so doing. Again what can not be change is "identity". — Bitter Crank

So sayeth the book of Bitter Crank (also sometimes known as the book of Total fill-in-the-blank).

The identity of an animal is determined by billions of base pairs of DNA. A creature's identity, once composed, is fixed -- that's my view. You don't have to agree with it. A rabbit is a rabbit; it can not become a wolf. a salmon is a salmon; it can not become a bear. Homo sapiens are a particular variety of primate, and there is nothing we can do about that. Nor should do. — Bitter Crank

Again, just a bunch of assertions, not an argument.

They're all demonstrably false too.

I take it you agree that your body was created from a sperm and an egg, yes? And so you accept, I take it, that sperms and eggs can become males and females?

If a sperm and an egg can become males and females, why can't a male become a female? You owe an argument, because the difference between a sperm, an egg, and a male is far, far more radical than ever the difference between a male and a female.

So, the idea that once a thing's identity has been determined - as in the case of a sperm, and an egg - it is therefore fixed, is farcical.

I mean, as far as you're concerned nothing can change! If something is blue, it is always blue. If something is square, it is always square. And so on. A more obviously false view is hard to conceive of.

Er, no. I've watched youtube videos on it and they are no different to listening to one of you - that is, they seem as confused as someone who thinks time travels more slowly in fridges.

If you understand what the difference is - the difference that allows an inference to be made about time in the one case but not in the other - then explain it in your own words, please.

Motion by definition is relative. — noAxioms

Er, no, it really isn't.

I have a hard time thinking in such terms, as I said, you should go with it. — noAxioms

I don't see why I should as it really isn't hard to think in such terms. But anyway, I did. And then you said one was stationary. And I explained why this isn't the issue - we're not talking about space and motion, but about time. So, how does the example show us anything about 'time'?

In absolute interpretation, light speed is not frame independent. That's where it becomes complicated. Has nothing to do with apples. — noAxioms

It has everything to do with apples - I brought apples into it and wanted to know why those who think the twin paradox shows us something interesting about time aren't as confused as someone who thinks that because an apple in the fridge decays more slowly than one on the sideboard, therefore time travels more slowly in the fridge.

So far you have singularly failed to do this - indeed, from your previous comment it seems that you think time does actually travel slower in the fridge.

If you don't think this, can you explain the difference between my apple example and the twin paradox?

If the apples move fast, then yes, one actually gets older than the other. This has been demonstrated conclusively with small fast objects that decay at very known rates. — noAxioms

Hahaha, so you DO think time goes more slowly in fridges?! It has been demonstrated conclusively that apples decay more slowly in fridges.

The apple in the fridge on the sideboard does not 'age' faster than the one in the fridge. They are both the same age. One is just more shrivelled than the other. Processes have happened in one faster than they have in the other.

The simplest case then is Earth is arbitrarily designated as stationary and Bob moves fast the whole time and thus ages less because physical processes slow down if they're not stationary. That's actually pretty simple, and the twins thing isn't a paradox at all. Reference frames don't come into play at all with this interpretation. Why don't you go with it? — noAxioms

Er, I did. And then you said both move.

What I want to know is why physicists think it tells us something interesting about time. Because it seems to me to tell us nothing more than my fridge/apple example.

For instance, here's another variation: one twin travels from the earth and the other stays put. Twin one thinks "hm, my twin is getting smaller and smaller than me". Whereas the other twin - twin two - thinks "hm, my twin is getting smaller and smaller than me".

Are they both getting smaller than each other? No, obviously not. But they both have equally justified beliefs that one is getting smaller than the other.

Doesn't matter - same point applies. They both speed away and then come back together, yes?

THey won't both be older than each other, will they? So, what's the point?

is it that under such a scenario two people will find themselves with contradictory but equally well epistemically justified beliefs about how much time has elapsed?

The original set up is that one is stationary and the other travels away at a constant speed, yes? And they turn around and travel back, yes?

And the 'paradox' is, well, what? That one will 'think' that they have experienced less time than the other, and the other will think the reverse, yes?

And that's somehow supposed to tell us something about time?

I mean, they can't actually both be older than each other, yes? So they've endured for the same amount of time. It is just they don't think this, based on their experiences.

Just as, by analogy, the apple in the fridge, though it appears not to have endured as much time as the apple on the sideboard, has, in fact, endured the same amount of time.

It would be monstrously silly to conclude that appearances are accurate and that time slows down in fridges. And so it would surely be every bit as silly to conclude that the appearances the twins are subject to are accurate.

BTW, the apple example is more like gravitational dilation. An apple on the top floor of a building rots faster than one on ground floor, all else being equal. — noAxioms

We're agreed, though, that the apple in the fridge isn't travelling through time slower though, yes? Time doesn't run slower in fridges, or faster at the tops of buildings, presumably.

I am unclear why they can't meet up. If one is travelling through space and the other is stationary, why can't they meet up?

But they can meet back up, yes? And if they do, are they both older than each other?

So, when the twins meet back up, they're both older than each other?

If there are mental states, there is an object - a thing, called 'a mind' - that they are the states of or my premise: If there are mental states, there is an object - a thing, called 'a brain' - that they are states of is true. — TheMadFool

Again, one of those - mine - is an a priori truth of reason. Or do you think that it makes sense that a mental state could exist absent an object that it is the state of?

As I explained at length, just as it makes no sense to think that an object's shape could exist absent the object whose shape it is, so too it makes no sense to think that a mental state can exist absent a mind that it is the state of.

Your premise is obviously 'not' an apriori truth of reason. You've just built into it an arbitrary stipulation about the kind of object in question.

So you haven't reasoned - you haven't constructed an argument made purely of apparent a priori truths and observations and then seen what conclusion you get to. No, you've just stipulated in one of your premises that minds are brains.

So, once more, your argument is question begging and implausible.

Consider two detectives. They're at a crime scene and they discover a red hair on the knife that was clearly used to kill Marjory. The first detective infers from this that Marjory's killer most likely had red hair. That's all he infers, because that's all that piece of evidence permits him to infer.
The other detective infers not just that Marjory's killer most likely had red hair, but that Marjory's killer is called Ken. The second detective is a bloody idiot, yes? The red hair does not licence that inference - it is an unreasonable inference. Yes, it is 'possible' the killer is called Ken, because Ken is a name and killers have names. But the discovery of the red hair does not give the detective any special reason to think the killer is called Ken.

You're reasoning like the second detective. If there are mental states, that licences us to conclude that there is an object that is bearing them, but it doesn't licence us to conclude that the object in question is a brain. It might be a brain, because a brain is an object. But the existence of mental states - like the red hair - does not licence you to draw that conclusion, only to infer that there is some kind of an object (an object whose precise nature we've yet to determine) that is bearing it.

Well done for not engaging with what I said.

Has time passed more slowly for the apple in the fridge?

If 'no' (and obviously the answer is 'no'), what's the difference between that case and the twin case?

This thread is not about whether it is good or bad to change your sex, or whether you have a right to do so, but about whether it is 'possible' to do so. So it is, at root, a metaphysical question. For all the heat and emotion that surrounds it, the question is at base squarely philosophical and can - and should - be dealt with using the cold tools of reasoned analysis.

I pointedly used conditionals in the OP. I said 'if' sex is constitutively determined by physical features (including chromosomal structure) then it can obviously be changed.

That applies to ALL physicalist views about sex. All of them. Someone who thinks (implausibly) that a certain chromosomal structure is both necessary and sufficient for qualification as a male, or female, is someone who thinks sex can be changed. For chromosomal structure can, in principle, be changed. It's just hard to change it, that's all, and may currently be beyond our know-how.

Likewise if you think sex is constitutively determined by one's attitudes, either one's own or those of others, or some combination. Again: it can then be changed.

And likewise if you think it is a combination of the above (including disjunctive 'either/or' combinations).

Clearly, however, there are some here who think sex can't be changed. They're not really arguing their case, so far as I can tell, just asserting it as if it is common sense and doesn't require support.

Some of those clearly also think the sex is determined at the chromosomal level. I think they're either confused or dishonest, as a simple thought experiment will demonstrate.

Imagine that tomorrow scientists discover a very easy way in which chromosomal structure can be changed. All it takes is the consumption of a pill and, overnight, your chromosomal structure will be changed.

Now, will all of those who think sex can't be changed now alter their view and conclude that it can, in fact, be changed?

No. Of course they won't. They'll just shift the goalposts. You can get boobs gallore, vaginas all over your body and you can even change your chromosomes, they'll still notconsider you a woman if you weren't born with them.

That's a prediction - but it's true, isn't it? If getting boobs and a vagina doesn't do it for them, how plausible is it that changing your chromosomes will? Not remotely! They 'say' it is all about chromosomes, but it isn't because you can bet your house they won't consider you a woman no matter what changes you make to your body or your attitudes, or whatever. They'll never be satisfied.

That's the sense in which they're dishonest. All they're going to do is locate some physical feature that technological limitations mean you can't currently change and insist that changing sex requires changing 'that'. And then, when technology advances to allow you to change it, they'll say 'ah no, it actually in addition requires changing 'this'. And on and on it will go. They'll just keep refining their supposedly physicalist conception of sex so that changing it is always beyond your reach.

So what's their actual view - or better, (because they themselves are normally confused), what's the view that delivers this result? The historical view. That's the only view about sex that fixes it once and for all and will make changing it something you'll never be able to do. For with the historical view, changing your sex requires changing the past. And of course, that's something none of us are ever going to be able to do.

This is significant philosophically and epistemically.

It is significant epistemically because the historical view is just one view among at least four distinct kinds of view. At best only one of those views can be true. So, if three kinds of view permit sex to change, and one doesn't, then chances are sex can be changed. Other things being equal, it is three times more likely that you can change your sex, than that you can't.

It is significant philosophically because it means the 'can't change it' brigade need to defend that view - that view specifically - and it just isn't particularly plausible.

First, your view - that chromosomal structure is essential to sex - is implausible. And extremely implausible when applied to the issues that divide people (toilets, positive discrimination, that kind of thing). (And note, sex would still be changeable on your view, it is just that changing it would be more difficult).

Second, there can be disjunctive concepts - that is to say, multiple ways in which someone or something might answer to the concept in question. Take 'being unwell'. There isn't just one way in which someone can qualify as 'unwell' - there are all manner of ways in which one can qualify. It seems plausible that in practice our concept of sex is like that.

So, it does not follow from boobs and vagina qualifying someone as female, that possession of boobs and vagina is essential to being female.

why do you think the chromosomal structure of your cells is the crucial thing?

I have no idea what chromosomal structure my cells have (I've never inspected them). So let's say I do inspect them and find that they have the structure you think is required for being female and incompatible with being male. Am I now a female? Should I use the female toilet? Would it be fair for me now to benefit from positive discrimination programmes? (bracketing the issue of whether such programmes are justified at all, of course).

I think the answer to those questions is a fairly obvious 'no'. And vice versa. Someone whose cells happen to have the chromosomal structure that you insist is necessary and sufficient to qualify as a male, but who is in every other respect female, should surely use female toilets and fairly benefit from positive discrimination programmes designed to benefit women (for regardless of their chromosomal structure, they will have been - and/or will be - on the receiving end of the discrimination such programmes are designed - whether justly or not - to ameliorate).

It would be just bizarre, I think, to insist that unless or until the chromosomal structure of your cells is changed, you must use the male toilet or whatever. (Which, in turn, implies that our concept of a male and a female does not make essential reference to chromosomal structure).

So now we're back to the "if you had your sex changed on Tuesday, it was not changed on Thursday" kind of point. That is to say, a pointless point.

Only now it seems you really think that sex can't be changed (which was implied by a lot of your language anyway). Yet earlier you'd acknowledged that it could be.

If you think sex can't be changed, why?

If sex is constitutively determined by physical features, then it can clearly be changed, for we do not have any of our physical features essentially.

If sex is constitutively determined by social features, then it can equally clearly be changed (for we do not have any attitudes or roles 'essentially').

If sex is constitutively determined by some combination of the above, or some disjunction of the above, then it can clearly be changed (for all of the above can be changed).

Note: really changed, not disguised.

It is only if our sex has an essential historical component that it would be unchangeable (due to the fact that we can't alter the past). But 'that' conception of sex is, a) pretty implausible and b) even if true, it would only show the irrelevance of that notion of sex to the issues that divide people.

That's just not true. First, nature doesn't 'decide' anything (nature isn't a person). And second, the whole point is that it is not 'disguising', but altering. That's a big difference. Someone who changes their sex has changed their sex, not disguised it. You seem to be giving with one hand and taking with the other.

You said that sex changes are artificial - well a) they're not necessarily artificial and b) that's a pointless observation. It is 'as' pointless a pointing out that a sex change that occurs on a Wednesday does not therefore occur on a Thursday. That observation at least has the merit of being true, but it is completely pointless.

So, someone who uses human means to change their sex has not had their sex changed naturally. Okay - so? What's your point?

It’s less pointless than your observation that one can change their sex by altering their body. You can change someone’s skin color by giving them a tattoo. You can change their hair color by dying their hair. These are artificial, not naturally occurring. — NOS4A2

Again, more pointless observations.

Me: you can change your sex.

You: yes, but if you change your sex on a Wednesday, you didn't change it on a Tuesday

Me: that's a pointless observation in this context

You: yes, but if you change your sex on a Thursday, you didn't change it on a Friday

Adding more pointless observations to an already pointless one does not a point make.

Why are you invested in the idea that nothing has an inherent identity? — Bitter Crank

Where did I say that? I don't think you know what the words you are using really mean.

The simplest way of turning pigs ears into silk purses would be — Bitter Crank

You earlier said that you cannot turn a pig's ear into a silk purse.

I then explained that you could, it is just tremendously difficulty and possibly beyond our technical know-how.

You're now telling me the easiest way to do it. To do something, note, that you previously said was impossible! So, is it possible or not? (Don't try and answer).

One of the sleights of hand that pro-trans advocates pull is saying "sex is assigned at birth". Not true. Sex is observed at birth. Hospitals, doctors, midwives, and parents don't arbitrarily "assign" a sex at birth. — Bitter Crank

Question begging - you're assuming that sex is constitutively determined by a collection of physical attributes (that's precisely what many would dispute, so you can't just stipulate that it is without offering some kind of defence). But even if that's correct - that is, correct that sex is constitutively determined by a collection of physical attributes - that is consistent with sex being able to be changed. "At birth" and "unalterable" do not mean the same thing. I was very small at birth, I am now very big.

Penis? check = male
Vagina? check = female
XY chromosome? check = male
XX chromosome? check = female — Bitter Crank

Again, just question begging and ignorant and unargued.

If I pull my penis off, I do not thereby cease to be a male. Plus, even if penises and vaginas are necessary and sufficient to qualify as male and female respectively, that wouldn't mean sex is fixed for someone with a penis can lose the penis and acquire a vagina and vice versa.

And likewise for chromosomes. Nothing in principle stops us from changing our chromosomes, it's just very difficult. You do not have your chromosomal structure essentially (which is not, note, to deny that you have some essential features).

Plus let's say that you discover that, much to your surprise, you have 'female' chromosomes. Well even if that means that, contrary to what you and others have believed up till now, you are in fact a woman, that wouldn't plausibly mean that it is ok for you to benefit from positive discrimination programmes designed to benefit women, or to use women's toilets, or to go to a female prison if you've done wrong. And vice versa - if someone who has up until now been considered by herself and everyone else to be a woman discovers that she actually has male chromosomes, it wouldn't be fair to insist she now use male toilets and cease to have positively discrimination programmes designed to benefit women apply to her.
By contrast, someone who has 'male' chromosomes but is otherwise indistinguishable from a 'woman' (I'm putting them in inverted commas because I don't accept the chromosomal view), should, of course, use the female toilet, benefit from positive discrimination programmes designed to benefit 'women' and go to a female prison if convicted of something. (Not saying indistinguishability is necessary for these things, just sufficient).
So even if someone insists that the chromosomal view is correct - and I personally think it isn't - this a) doesn't entail that one cannot change sex and b) is actually irrelevant to all the issues that divide people.

Transexuals usually have a perfectly normal body; the idea that their identity does not match their body is a delusion. Look, I completely understand that some men would rather be women and some women would rather be men. They can pretend. I might wish I looked like Adonis, sang in a baritone voice, possessed the mind of Einstein, and had the wealth of Bill Gates, but I don't. They can have organs lopped off or sort-of-look-alike organs fashioned out of skin and fat tissues. An artificial penis is not a real penis; a glass eyeball is not a real eyeball. — Bitter Crank

I couldn't detect an argument in any of that, just more question begging stipulations.

I mean, how on earth does it follow from a glass eyeball not being a real eyeball that transsexuals are not therefore the sex they say they are?

That's both false and a pointless observation if true. It is false because from the fact a person's sex can be changed it does not follow of necessity that all such changes are by humans rather than by other natural processes. And even if true - which it isn't - it would be a pointless observation of no philosophical importance.

You're both right. If we define sex solely in terms of external anatomy, then certainly the sex can be changed. If we define it in terms of the presence or absence of a Y chromosome, then sex cannot be changed. — Relativist

They're both wrong, and you're wrong. We can change internal features as surely as we can change external ones. So if sex is constitutively determined by some arrangement of physical features, then a person's sex can be changed. Not just apparently changed, but actually changed.

Can you make a silk purse out of a sow's ear? I think not. — Bitter Crank

Yes you can, it's just tremendously difficult and probably beyond our technical know-how at the moment. For with sufficient changes you could turn a sow's ear into a silk worm. And then one could make silk from that former sow's ear and use it to make a purse.

Your argument was a) not a version of my argument (you represented it to be), b) not sound, c) flagrantly question begging.

The only similarity between your argument and mine is that your argument is valid (like mine) and it shares the same second premise.

You can construct valid arguments until the cows come home. What you need to do is construct one that is plausibly sound and not flagrantly question begging (that is, one that does not just stipulate on the contested issue as opposed to appealing to rational appearances).

So, here's a really rubbish argument.

1. If there are mental states, there is a million mile long crocodile that they are the states of
2. There are mental states
3. Therefore there is a million mile long crocodile that they are states of

What is that shit? It's valid. But it's shit because premise 1 is grossly implausible. It is not an a priori truth of reason - that is, it is not something that our reason says is true, independent of experience. And there seems no reason provided by any experiences we have had either. So it is just stupid.

By contrast, my first premise says only this: if there are mental states, there is an object that they are the states of.

Now that 'is' an a priori truth of reason. The idea of there being mental states existing by themselves doesn't make sense - it is akin to thinking that a physical object's shape can exist absent the object whose shape it is. Imagine going into a shop and seeing an object you like and asking how much it is. $40 you are told. Oh, I haven't got $40 on me - how much for the shape alone? You'd be asked to leave, yes? Because what you've asked is crazy - it makes no sense.

Why? Because 'shape' is a state of a physical object. Physical objects have shapes. Shapes are not things, even though many things are shaped.

Likewise, mental states are states of an object. They are not things in their own right - they are 'states of a thing'.
What kind of an object they are the states of is what subsequent reasoning about this can reveal. You can't just stipulate.

So again, your argument is a) not a version of mine; b) unsound; c) question begging.

You're contradicting yourself. If you can change your sex - and I've argued you can, and you've accepted that you can - then the change is not artificial, but genuine. You haven't merely appeared to change your sex, you actually have.

Argument? 'Philosophy forum' not 'arbitrary stipulation forum'.

Can you make a silk purse out of a sow's ear? I think not. — Bitter Crank

And your point is?

It seems to me that you have reached for the wrong comparison here. Among progressives (who are all in favor of loosely defined gender definitions) there is very strong support for the idea that race is an arbitrary social construct than that it is an essential historical component. — Bitter Crank

First, this thread isn't about race, but sex. But anyway, all you've done is said some things, not defended anything. The fact is that race does seem to have an essential historical component, which is why a person is able to change their sex, but not their race. But even if you bother to present an argument showing otherwise, that wouldn't affect my point, would it? For if it lacks a historical component, then you can change it - like, you know, your sex.

In the real world there is a distinct difference between "what is, in fact the case" and "what one can get away with". In the real world, males have XY chromosomes, and females have XX chromosomes. Men have penises, testicles, prostates, and so forth; women have vaginas, ovaries, fallopian tubes, and uteruses. Women can bear children; men can not, — Bitter Crank

Did you actually read the OP? First, what is or is not needed to qualify as one sex rather than another is a matter of debate, and as such you can't just stipulate. This is a philosophy forum, not a pub. Just barking loudly that 'men have penises' is not a case (and it is implausible anyway - I mean, if I jump naked over a barbed wire fence and misjudge things and it rips my penis off, am I no longer a man when I land?). Second, my point is that even if qualification as a particular sex requires possession of some particular set or sets of physical features, the simple fact is that physical features can be changed and thus sex can be changed.