Showing posts with label thought experiments. Show all posts
Showing posts with label thought experiments. Show all posts

19 September 2021

The Cow in the Field and the Riddle of What Do We REALLY Know?


P
i looks at a wide range of things that go well beyond the scope of academic philosophy, but that shouldn't mean that we can't occasionally return to the narrow path. Talking with existentialists at a new website (that I would recommend to everyone) called Moti-Tribe,  brought me back to thinking about one of my favorite philosophical problems,

This is the story of ‘The Cow in the Field’ that I came up with many years ago at a time when the academic (boring) philosophers were obsessed with someone who had some coins in his pocket but weren’t sure exactly what they were, and calling it grandly, the ‘Gettier Problem’.

You’d have been forgiven for being put right off the issue by how the academics approached it, but indeed, the riddle is very old, can be tracked back certainly to Plato and is indeed rooted even further back in Eastern philosophy where the assumption that we don’t know things is a part of mysticism and monkishness that we don't really understand anything about.

It’s a kind of koan, which as I understand them, the point of which is to startle you out of your everyday assumptions and oblige you to think more intuitively. The conventional account is that they are a tool of Zen Buddhism used to demonstrate *the inadequacy of logical reasoning* - and open the way to enlightenment.

Well, once you explore the origins of Western philosophy, and the ideas of people like Pythagoras, Heraclitus, Socrates and Plato, you soon find out that there is a lot of riddling actually going on. And the reason why is exactly the same: in order to demonstrate this inadequacy of logical reasoning and provoke enlightenment.

Slightly bizarrely, conventional books and courses on philosophy seek to reinvent ancient philosophy to make it all about ‘the discovery’ of logic! But Western philosophy and Eastern mysticism are two sides of the same coin, we can learn from both.

So on to the puzzle!

THE COW IN THE FIELD


Imagine a farmer who has rather fine cow called Daisy. He is so proud of his cow that he often checks up on her. In fact, he is so concerned that one day, when he asks his dairyman how Daisy is doing, and the Dairyman tells him that Daisy is in the field happily grazing, the farmer decides that he needs to know for certain.

He doesn’t want to just have a 99% idea that Daisy is safe, he wants to be able to say 100% that he knows Daisy is okay.

The farmer goes out to the field and, standing by the gate, sees in the distance, behind some trees, a white-and-black shape that he recognises as his favourite cow. He goes back to the dairy and tells his friend the dairyman that he knows Daisy is in the field. 



Okay, so what’s the ‘problem’? Simply whether, at this point, does our farmer really ‘know’ it - or does he merely think that he knows?

Pause for a moment and ask yourself what your intuition is. Because we have to allow that the farmer not only thinks that he knows, he has evidence - the evidence of his eyes we might say - for his belief too.

Anyway, you maybe still think that there’s some doubt about him really knowing, but then we add a new twist. Responding to  the farmer’s worries, the dairyman decides that he will go and check on Daisy, and goes out to the field. And there he does indeed find Daisy, having a nap in a hollow, behind a bush, well out of sight of the gate. He also spots a large piece of black-and-white paper that has got caught in a tree. Point is, yes, Daisy WAS in the field, but the farmer could not have seen her, only the piece of paper.

So the philosophical debate is, when the farmer returned from the field after (as he thought) checking up on his cow, did he really KNOW she was in it?

Because now you see, it seems that Farmer Field has satisfied the three conventional requirements for ‘knowledge’.

• He believes something,

• he has a relevant reason for his belief,

• and in fact his belief is correct...

Philosophers say that he had a ‘justified true belief’. And yet we would not want to say that he really did know what he thought he knew. In this case, that his cow was in the field...

It's a simple story, okay, silly if you like, but entirely possible. And what the possibility shows is that the three conventional requirements for knowledge are simply not enough to give certainty. What THAT implies, is that we know nothing!

Which is back to the Eastern philosophies, which put so much more emphasis on what we don't know - and seek exotic ways to compensate.

07 September 2020

‘Mary’s Room’: A Thought Experiment

Posted by Keith Tidman
Can we fully understand the world through thought and language—or do we only really understand it through experience? And if only through experience, can we truly communicate with one another on every level? These were some of the questions which lay behind a famous thought experiment of 1982:
A brilliant neurophysiologist, Mary, knows all there is to know about her academic specialty, the science of vision: the physics, biology, chemistry, physiology, and neuroscience. Also how we see colour.

There’s a catch, however: Mary has lived her entire life in a totally black-and-white room, watching a black-and-white screen, and reading black-and-white books. An entirely monochromatic existence. Then, unexpectedly, her screen reveals a bright-red tomato.

What was it like for Mary to experience colour for the first time? Or as the Australian philosopher Frank Jackson asked, who originated this thought experiment, ‘Will [Mary] learn anything or not?’ *

Jackson’s original takeaway from his scenario was that Mary’s first-time experience of red amounted to new knowledge—despite her comprehensive scientific knowledge in the field of colour vision. Jackson believed at the time that colour perception cannot entirely be understood without a person visually experiencing colour.

However, not everyone agreed. Some proposed that Mary’s knowledge, in the absence of first-hand experience, was at best only ever going to be partial, never complete. Indeed, renowned philosopher Thomas Nagel, of ‘what is it like to be a bat’ fame, was in the camp of those who argue that some information can only be understood subjectively.

Yet, Mary's complete acquaintance with the science of vision might well be all there is to understanding the formation of knowledge about colour perception. Philosopher and neurobiologist Owen Flanagan was on-board, concluding that seeing red is a physical occurrence. As he put it, 'Mary knows everything about colour vision that can be expressed in the vocabularies of a complete physics, chemistry, and neuroscience.

Mary would not have learned anything new, then, when the bright-red tomato popped up on her screen. Through the completeness of her knowledge of the science of colour vision, she already fully knew what her exposure to the red tomato would entail by way of sensations. No qualities of the experience were unknowable. The key is in how the brain gives rise to subjective knowledge and experience.

The matter boils down to whether there are nonphysical, qualitative sensations—like colour, taste, smell, feeling, and emotion—that require experience in order for us to become fully familiar with them. Are there limits to our comprehension of something we don’t actually experience? If so, Mary did learn something new by seeing red for the first time.

A few years after Frank Jackson first presented the ‘Mary’s room’ thought experiment, he changed his mind. After considering opposing viewpoints, he came to believe that there was nothing apart from redness’s physical description, of which Mary was fully aware. This time, he concluded that first-hand experiences, too, are scientifically objective, fully measurable events in the brain and thus knowable by someone with Mary’s comprehension and expertise.

This switching of his original position was prompted, in part, by American philosopher and cognitive scientist Daniel Dennett. Dennett asserted that if Mary indeed knew ‘absolutely everything about colour’, as Jackson’s thought experiment presumes, by definition her all-encompassing knowledge would include the science behind people’s ability to comprehend the actual sensation of colour.

To these points, Mary’s factual expertise in the science of colour experience—and the experience’s equivalence and measurability in the brain—appears sufficient to conclude she already knew what red would look like. The experience of red was part of her comprehension of human cognitive functions. Not just with regard to colour, but also to the full array of human mental states: for instance, pain, sweetness, coldness, exhilaration, tedium—ad infinitum.

As Jackson ultimately concluded, the gist is that, given the special particulars of the thought experiment—Mary acquired ‘all the physical information there is to obtain about what goes on when we see ripe tomatoes, or the sky, and use terms like red and blue’—Mary did not acquire new information upon first seeing the red tomato. She didn’t learn anything. Her awareness of redness was already complete.



* Frank Jackson, 'Epiphenomenal Qualia', Philosophical Quarterly, 32, April 1982.

31 August 2020

Thought Experiment: How do you Price the Office Parlour Palm?

Posted by Martin Cohen
Here's one of a collection of short puzzles that might be considered an A-Z of the tricks of high finance: Not so much 'P is for Parlour Palm' though as 'C is for Cheap Collateral'.

This is the idea that if a bank agrees to loan the office parlour palm to the next door bank for a million dollars, and in return to rent their aspidistra for a million dollars, they both can update their asset sheets accordingly!

Now that's magic. But it was also the basis of the B for Bubble that brought down most of the world's banking system in 2008!

Of course, banks don't do silly stuff like buy each others' pot plants. But they do buy each others' packaged securities. And for many years, these packages became more and more complex, and thus more and more about buyer and seller agreeing on what mysterious qualities made the deal realistic. We know where that ended up: with thousands of dodgy loans to people who had no income or maybe had even died being bundled up and sold as top quality assets. Banks are plagued by problems with so-called ‘ghost’ collateral that disappears or is pledged to several lenders at the same time! After the crisis, the European Central Bank looked at the use of such devices and in a discussion paper wrote:

"the use of collateral is neither a sufficient nor a necessary condition for financial stability."*

The logicians could not have put it better!


https://www.ecb.europa.eu/pub/pdf/scpwps/ecb.wp2107.en.pdf

01 January 2017

Picture Post #20 Olber's Paradox raising insoluble questions



'Because things don’t appear to be the known thing; they aren’t what they seemed to be neither will they become what they might appear to become.'


Posted by Martin Cohen and Tessa den Uyl

A NASA  image from the Hubble Telescope looking into the 'Deep Field'
This is a patch of BLACK sky - empty when initially seen - even through the largest earthbound telescopes. Yet, with the  Hubble space telescope and a long-enough exposure time, even the darkness of space soon comes to glowing life. The point is, every bit of sky is actually packed with light - not merely with stars but with uncountable distant galaxies.

Heinrich Olbers (1758–1840) was a Viennese doctor who only did astronomy in his spare time, but realised that there was a bit of a logical problem about the night sky. And ‘O’ is for ‘Olbers Paradox’*,  which can be summed up by saying that if the universe is really infinite in size, the the night sky should not only be bright – but should be infinitely bright. Put short, we should see stars everywhere we look. So why don't we and why isn't the night sky all lit up ?

The paradox touches upon profound issues in cosmology, or the study and theory of the origins of the universe. Simply saying that most of the stars are too far away to see is not enough. Certainly it is true that starlight, like any other kind of light, dims as a function of distance, but at the same time, the number of light sources in the ‘cone of vision’ increases – at exactly the same rate. In fact, on the mathematics of it, given an infinite universe, with galaxies and stars distributed uniformly, the whole night sky should appear to be not black, not speckled, but white!

Olbers’ paradox is a ‘thought experiment’ in the very good sense that most of the reasoning is done by hypotheticals. What if the universe is infinitely large? And infinitely old? If the stars and galaxies are (on average) spread out evenly?

Various possible explanations have been offered to explain the paradox. Such as that stars and galaxies are not distributed randomly, but rather clumped together leaving most of space completely empty. So, for example, there could be a lot of stars, but they hide behind one another. But in fact, observations reveal galaxies and stars to be quite evenly spread out.

What then, if perhaps the universe has only a finite number of stars and galaxies? Yet the number of stars, finite or not, is definitely still large enough to light up the entire sky…

Another idea is that there may be too much dust in space to see the distant stars? This seems tempting, but ignores known facts. Like that the dust would heat up too, and that space would have a much higher. The astronomers who took this image claim it shows some kind of spectral shift into the red specturm. Or is it only the dust? The questions are not really resolved, even yet.

So what is the best answer to Olbers’ riddle? The favoured explanation today is that although the universe may be infinitely large, it is not infinitely old, meaning that the galaxies beyond a certain distance will simply not have had enough time to send their light over to fill our night sky. If the universe is, say, 15 billion years old, then only stars and galaxies less than 15 billion light years away are going to be visible. Add to which, astronomers say that the phenomenon of red shift may mean some galaxies are receding from us so fast that their light has been ‘shifted’ beyond the visible spectrum.

After reading this, and then standing here on planet Earth and watching the night sky, one might feel a little trapped by the questions. Our sight is limited and it always will be but maybe this is our hope for we can continue to philosophise: afte rall, what are we thinking? The picture above might as well represent pieces of coloured glass, under water visions where fluorescent life flows in deep dark sees, a pattern for printed cloth. Our brain only represents what we think we see, not necessarily the reality in which we live? In the incredible immensity of space, mankind has always been aware of this, even if, once in a while, the tendency is to forget.


* Although the paradox carries Olbers’ name,  it can really be traced back to Johannes Kepler in 1610.  In Wittgenstein's Beetle and Other Classic Thought Experiments, Martin’s book, which talks a little more about all this,