Except that you can't because you might have Z coloured eyes and although you can see that the others don't have Z coloured eyes, they don't know that, and so they cannot make the deduction that you rely on them making, to make your deduction

they will correctly deduce their eye colour (unless they have a unique eye colour). — Michael

But since they do not know their eye colour they might all have unique eye colours and none of them can deduce their eye colour at all. Guess and hope is not deduction.

If you want to get better at stuff like this, you need to learn from the master, Raymond Smullyan.His puzzles are wonderful and such talent as I have is down to reading a couple of his puzzle books, a long time ago. I almost didn't answer because I suspected this puzzle was one of his, and the answer came so intuitive and so quick, I thought it was one I knew but had forgotten. Mind, at one point @Michael got me so confused I said something completely wrong about brown eyed people leaving later.

Anyways, Smullyan - The Lady and the Tiger - or any of his logic puzzles are recommended to all.

Focus on what everyone does not know which in each case is only the colour of their own eyes. Now as soon as anyone does know, they are gone, and you know that they knew. Imagining and guessing are not ever allowed in deductive logic so if nothing is said, no one can ever know and thus nothing can ever change.

So someone says I see blue. And now we all know that if anyone did not see blue, they would be blue, and they would know they would be blue and be gone tonight. We know that we can see 99 blues, but that doesn't change the logic, because it's counterfactual conditional.
So tomorrow, we know that everyone can see at least one blue because no one left. But if anyone could only see 1 blue, they would know that, since that one blue did not leave, they themselves must be blue too. And in that case they would both leave that night. And so as each day passes, the counterfactual argument gets augmented by "but no one left therefore everyone must see one more blue", until it gets just exactly to the number of blues (which remember no one exactly knows, because they do do not know their own colour) So after 99 days you know that all the blues are seeing 99 blues, and you are seeing 99 blues and therefore you must be the extra blue that all the other blues must be seeing - because they cannot see themselves. You can see that no one else is.

And at this point I really cannot be arsed if anyone still doesn't get it. I done my bestest and thunked hard how to explain it - Over and out.

You are a logical person who does not know their eye colour; so is everyone else.
You know everyone's eye colour except your own, and everyone else knows your eye colour but not in each case their own.
So to know the colour of your own eyes you need to compare what you see to what they see. Now as each day passes with no blue eyed people leaving, the minimum number of blue eyes each blue eyed person must be seeing increases by one. [Whereas a brown or green eyed person will see one more.] So if you are seeing 2 blue-eyes and they haven't left on the second night, they must also be seeing (at least) 2 blue-eyes, which means you must have blue eyes since they cannot see their own eyes and you can see everyone's but your own.
So when the days have passed that equal the number of blue-eyes that you see, that minimum requires that you have blue eyes too, otherwise the blue-eyes would have already gone. In which case you, and of course all the others remaining must have brown, grey, violet, green, or some other colour eyes, though as it happens you know as they each don't that they all have brown eyes except the guru.

Why should the step "If there were one blue, they would leave on the first day" appear in the brains of perfect logicians who already knew before the guru spoke that this was not the case? — hypericin

It's a counterfactual conditional from which valid deductions can be made thus:

If wishes were horses, then beggars would ride.
But beggars do not ride, but have to walk.
Therefore wishes are not horses.

I'm done with arguing here, but looking around there are plenty of wrong answers about, but here is a fairly decent run through.

https://xkcd.com/solution.html

No it doesn't. It only depends on "the Guru sees at least one blue-eyed person" being true. It doesn't depend on her saying so. — Michael

No. It does depend on the guru saying so unless everyone already knows that everyone already knows at the same time, as I suggested above and you ignored. This is the extra information that the guru imparts: she doesn't inform them about what she sees, but she puts everyone in a synchronised state of knowing each other's knowing. That is what is required for the nested hypotheticals to begin.

I reason thus:
If there was only 1 person with blue eyes {PWBE} and that person knew that the guru sees blue eyes, then that person would know that they have blue eyes and would leave tonight.

Therefore:
If there were only 2 PWBE and the guru sees blue eyes {GSBE} then neither would leave tonight, and when they see that, they each know they have blue eyes and would leave on the second night.

And so on.

But the factual knowledge that I can see multiple blue eyes and thus already know that the guru can see blue eyes cannot be imported into the counterfactual hypothetical wherein the blue eyed person would know no such thing because he would not himself see blue eyes, and thus could not know therefore that the guru saw blue eyes ... wait for it ... UNLESS SHE SAID SO.

Did they all arrive on the same day, and do they all know that they all know that they arrived on the same day?

Also I think the brown eyed people would not know their eye-colour for another 99 days after the blue eyes left, but only that they themselves didn't have blue eyes.

Now that is indeed tricky.

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What is a big lie? — Tom Storm

Things go better with coke.

Wealth in the hands of the wealthy trickles down to the poor.

Poverty is caused by immigrants.

Hatred is the best cure for suffering.

A big lie is a comfortable or comforting lie. It proffers an easy solution to a hard problem; it typically puts the blame for one's suffering on someone else and suggests doing something unpleasant to them as remedy. It misdirects one's emotion as the conjurer misdirects one's attention. Meanwhile, the other hand picks your pocket.

"Trump lovers are racist" will do the same job, and sound better. — AmadeusD

Well I do imagine that Trump and his followers are anti-woke because I hear them say so. So then I look at the policies being followed and the institutions being dismantled, and assume that 'woke' is the opposite. But you're right, I am no expert in what to me is a mere derogatory epithet, and no doubt the experts in derogatory epithets have the right of it And there's grades of horseshit n'all. I'll leave you experts to it.

I would put it this way. Wokism is giving a fuck about someone else's difficulties in a complex society. One is 'awakened' to the problems of being disabled, disfigured, or in any varied form divergent from the average. It leads to such horrors as designated parking spaces, ramps alongside stairs, special needs education, protection in law against unfair discrimination on grounds of age, sex, or race, and those appalling and distracting sign language displays on woke broadcasts.

Edit: In essence it is a denial of the constitutional right to join witch-hunts.

If the Earth’s rotation truly stopped or slowed (which is what "the sun stood still" would physically mean), it would have had catastrophic global consequences, including massive earthquakes, tsunamis, and changes in atmospheric motion due to sudden deceleration. — Truth Seeker

Obviously God didn't do that; instead He will have suspended time, rather as one pauses a video. And then brought the chosen people out of the frame of the paused world into His own living room and allowed them to make a few changes and then re-enter the movie.

Or possibly, Bible literalism is bonkers. I don't much care either way.

Byker is a district of Newcastle on Tyne. I used to play the tune as a dance. The time signature is 9/8, but divided as three measures of 2 beats and one of 3. I didn't know there were words ...

Not in all cases but in most BECAUSE OF THE FEAR OF PUNISHMENT. When your stomach is empty, you haven't eaten from 2 days you don't give a damn about morals or right or wrong(of course they are some exceptions) So yeah the only thing keeping them back is fear of punishment, fear of getting caught and getting punished. This was one of the instances, there are many more if you want. — QuirkyZen

There is nothing evil about taking food if you are starving. Rather it is evil to refuse to share food when others are starving. At this point property law is not the arbiter of goodness.

Where they have for example a lot of power and can make the possibility of getting caught during evil acts very little and doesn't this work there — QuirkyZen

For sure, people can be evil, and sometimes they can be very powerful too, and 'get away with it'. But this is not a basis for generalising that every person in power and every person that might be in power will become evil. Most people, most of the time are polite, considerate, and kind to each other without any coercion, and without any fear, but just because it is a more pleasant way to be together.

Are you trying to say these hypothetical scenarios have nothing to do with reality or Did i misunderstood. — QuirkyZen

Yes. Your question removes all the give and take of social interaction and mutual dependence, and then suggests that humans in that condition would be immoral, and that this is "deep". I'm saying it is very very shallow unrealistic and a mere thought. What makes us human is not independence but dependence; it is our shared language and customs that give rise morality, because for instance, if we did not by and large tell the truth, then talk itself would have no meaning. So to strip away all that and then ask what is our morality is like asking what we would breathe in a vacuum. It is a wrong question, and any answer would mislead.

Are We all Really Bad People deep down

I'm reflecting on why people in an impossible thought experiment would be more real and deep than moms and dads and kids in this world.

And I've decided that they are not real or deep at all, but imaginary beings with no connections or relations to one another. But other people here seem to prefer to think that good and bad and human relations are imaginary.

God kills us all, innocent and guilty alike.
— unenlightened

In this context, it’s more accurate to say we’ve all killed ourselves - all are guilty. — Fire Ologist

You put your words into God's mouth, and I'll put mine. I will not say that infants are already guilty. Rather I will say "The Lord giveth, and the Lord taketh away." And perhaps it is a kindness that he spares them temptation, but it is not my business to make such judgements in His place. It is a matter for faith and doubt.

God kills us all, innocent and guilty alike. You can thank Him for the limited gift of temporary existence, or berate him for His cruelty and injustice, because that choice comes with the gift of human life. But don't hold your breath waiting for Him to appear in the Court of Human Rights.

You won’t be able to penetrate these things with natural reason alone. — Fire Ologist

Supernatural reason would be more applicable.

A different perspective:

Head in the clouds and head in the sand both leave your ass exposed. Keep your ass covered and under your tit, your feet on the ground, and your head on your shoulders.

I thought this was interesting, not so much as an update on the condition of Russia, but more as a warning to the US about where it is headed.



A society built on falsehood must inevitably collapse. This is a fundamental asymmetry; any system (particularly any living system) that relies on communication, relies on truth predominating over falsehood. As soon as falsehood predominates that equates to the end of communication and fragmentation has happened. I stop listening to the bullshit, and go my own way.

The best thing about Americans is their enthusiasm. Some people find studies in evolution a little dry.

Not this guy; he brings a whole ocean of excitement to the subject.

Since I was diagnosed with depression ... — javi2541997

Have you considered the possibility that you are not depressed, but that rather it is that the world is a bit shit? I have to say you don't come over as depressed, but as quite lively and animated. Is it all an act?

One is supposed to be happy, and thus to be unhappy is an illness. But no; I say it is healthy to be unhappy about injustice and misery and suffering even if one is not oneself so badly off. Don't mistake compassion for sickness. Do not go to your local doctor because a child is starving a thousand miles away. There is no pill that you can take that will nourish that child.

What came before the 'big bang' or after any 'end' remains unknown. — Jack Cummins

There is no time before time began, or after time ends, by definition. It's not that it's unknown, it's that there can be no such thing; these are limits to being such that 'before' and 'after' do not apply. There is nothing to know or not know.

Of course if you take a God's eye view - the view from eternity - then you can say "Before Abraham was, I am." That is, all times are present to God, and all places are here; the whole universe of spacetime is in His hand. But this is poetic talk that no one understands.

Good philosophy eats itself, and can always be summed up as "The worm turns."A philosophical tradition is thus a daisy chain of linked worms. {Hands up who even knows how to make a daisy chain these days} Always one wants to start again from scratch, and always one cannot, because one has to thread one's way through the errors of historical philosophy one was brought up on.

But this time I'm going to manage not to bite my own tail. — Every Philosopher Ever

Don't talk with your mouth full. — unenlightened's mother

I think you're going off-topic for this thread. — Mark S

Then I wish you well and will not disturb you further.

Everyone should have an 'unname'. You unheard it here first!

Thou and I, of course are independent minded, and make up our own minds about what we want or don't want. But "the public" are so easily swayed by the media, that 'what they want' at any moment is largely whatever they are told they want at the moment.

So more or less whatever you hear about what the public wants or doesn't want becomes true by being said a few million times. They are not interested in politics, until they are told that politics is important and everyone is interested in politics. And then they demand a referendum on whatever topic is so important suddenly; and aren't we all so much happier and better off now we have escaped the terrible clutches of the EU?

Except that for some reason governments still cannot control our borders, and Johnny Foreigner is still coming here and spoiling everything for us. Fortunately there is a wonderful new party that the public are getting behind that will be able to sort this out as soon as we elect them. Hurrah for the earnest wants of the public that they have all thought through for themselves and decided on; and boo to all the foreigners making us poor and miserable.

The most brilliant propagandist technique will yield no success unless one fundamental principle is borne in mind constantly and with unflagging attention. It must confine itself to a few points and repeat them over and over. Here, as so often in this world, persistence is the first and most important requirement for success. — Adolf Hitler

Stable ecosystems are better understood as stable competition with some examples of cooperation for mutual benefit. — Mark S

Have to disagree with this. Take a living human body as a typical fairly stable dynamic environment. Around half the cells in the body are non-human see here (The figures have recently been revised in favour of the human cells a bit, I think, but the ball park is little changed). And for most of us, most of the time, cooperation dominates, to the extent that without the right gut biome, for instance, one would be unable to digest food. When 'competition' sets in, one is ill, and sometimes one loses the competition and dies.

At the level of genes, game theory applies, and it does not require that participants understand the theory, merely that they have 'interests' (which in this case we impose on them because we are only interested in the ones that survive.) Genes themselves of course have no interest either way, they have an effect on the organism, and either survive to reproduce or not. We call those that survive 'winners' and call their effects 'self-interested'. And we call that equivalent behaviour in ourselves, 'rational'.

So let me put a little challenge to you, because what you say above about the predominance of competition is the received wisdom that founds also the terminology of game theory, and a deal of politics too: if self interest is rational, then reason it out for me. Because in fact game theory is symmetrical, and evolution works just as well if we call the survivors the losers; the aim of life is to go extinct and 99.9% have managed to find their rest sooner or later, and we are the unlucky ones who have to carry on a bit longer.

'I am non-binary' means I am conservative with my stuff, but prepared to be liberal with your stuff.

The universe is lazy and always takes the line of least effort. So it becomes a creature of habit.

Ends are things that can be found in space and time The end of the day, the ends of a piece of string, the end of my life. (I know you rider)

The end of space, or the end of time does not quite make sense. One imagines the clock stopping, but in order for the clock to stop, time must continue while it stands still. So time might have stopped between my typing my first word and my second word of this post for a quintillion centuries, but since nothing happened, it makes no difference - the world - like a paused video, carries on just as before when play is continued. There is no room for experience at the end of time; it does not happen, and it not happening is what it is.

Morality as Cooperation. — Mark S

Have you thought about cooperation in nature, apart from between humans? Bees and flowers, the symbiotic relationship that produces lichens, ant colonies, and so on; it seems there is in every aspect of relations between an organism and its environment elements of cooperation and of exploitation.

A tiger creeps through the long grass towards its prey, and the vertical stripes and slow sinuous movement convey its absence - 'just the grass rustling in the breeze'. Or the reverse deceit of the prey, as a stick insect stands immobile at just the right angle and in the right place to appear to be a dry twig. Examples of an evolved form that cooperates with the general environment to deceive, on the one side its prey, and on the other, its predator.

Or the icon of immorality - the cuckoo; that lays its eggs in another bird's nest and whose offspring will kill all the chicks of its host, and be fed by the unhappy parents 'til it is bigger than them and they are exhausted.

Everybody dies, but what's the rush?

Some paleoanthropology for your delectation; focussed for a change on China and the far East. A gentle ramble, but with some interesting science and good discussion.

Ethics includes the morality, or lack of it, of our moral sense’s intuitions and past and present cultural moral norms. — Mark S

I really like this. It makes a great starting place by indicating that we have intuitions and make moral judgements not only with them but also of them.

Our moral intuitions are foundational to moral philosophy. I am interested to hear how you defend the idea that understanding why our specific moral intuitions exist is not relevant to moral philosophy. — Mark S

I don't. Here for random example, we discover that infants have intuitions about fairness that relate closely to the needs of a cooperating social animal for mutual trust. Clearly this can give rise to some internalised conflict with the appetites of the individual, and so sets up the endless psychodrama between the individual and society, and explains why conflict sociologists find that the more internalised conflict in a society, the less external conflict, such that a polarised society tends to descend into violence, whereas one of individuals with conflicting loyalties will be more peaceful.

My main goals here are to clarify why “morality” as moral ‘means’ (cultural moral norms and our moral sense) exists so we can 1) refine cultural moralities to better meet our need and preferences, 2) separate out the search for moral ‘ends’ that are the other part of the larger subject, ethics.

What is your goal here? — Mark S

My goal in this discussion is the same as my goal in every discussion, to arrive at the truth together. But particularly to this topic it is important to me to point out that our communication is necessarily a moral endeavour. And thus I close the circle back to those intuitions by which we judge the very investigative discourse on which we are embarked. Are our goals moral?

It is this circularity that allows ethics to take flight and transcend mere biology to become that which can stand in judgement of nature itself.

I submit this as evidence:

The argument is very simple and it is addressed to you as an individual who has made the quoted statement. But it applies equally to anyone who participates in these discussions. We only share our talk here, so nothing is at stake but the truth. And if there is no truth, then there is no meaning. Therefore our discourse has to presume a moral commitment to truth. even when, as now, it is painful. There is no sarcasm; I am in deadly earnest. We owe each other honesty, or we are not communicating at all.