Feynman says a lot of people have very fragile knowledge, and gives a couple examples where they know the answer to a problem, but then you change the problem a little, and basically the same answer would work, but they don't realize it. they know it, but they don't know how to apply it very well, unless it's asked in exactly the same way as when they learned it.

This stood out to me especially because of the word 'fragile' applied to know. I've used that word too, but I've never heard it done anywhere else. My idea (which is probably due to David Deutsch or to Kolya Wolf) can be explained a couple different ways.

One manifestation is that if someone is really interested in something, when they learn it, and they think about it a lot, then they will understand it in depth, and from lots of different angles, and they will figure out how to use it in lots of different ways, and they will integrate it with all the other things they know, so it plays a useful role in their overall way of thinking about the world. That's knowledge that *isn't* fragile, it's robust. Towards the opposite end of the spectrum is when you learn something the day before a test, and just try to remember the exact question that is likely to be on the test, and the answer. If you learn it like that, you'll probably forget after a couple days, and you never learn how to apply the idea to other issues -- that's fragile knowledge. I call it 'fragile' because it breaks very easily. You just change the problem situation a little and suddenly it stops working. It's not robust.

One way fragile knowledge gets created is when people are forced to learn something. Maybe you can make them learn the specific answers to the exact questions you ask, if they are scared enough of displeasing you. But that's never going to make them think about it, on their own time, for fun, and integrate the ideas into their personality, and make it a part of how they see the world. Quite the opposite. They are going to have really bad feelings attached to it, and avoid it when they can, and not see any of the ways to apply it to more of life.

Another way fragile knowledge gets created is when people do work purely for the money. Then they solve the exact problem their employer wants solved, and that's it, and they don't think about how they could use the stuff they are doing in more ways, cause they only care about the money and not the knowledge.

Another idea is that this connects to structural epistemology, and different knowledge structures can be more or less fragile. Almost no one knows what structural epistemology is, except computer programmers, but they aren't philosophers, so they don't know what epistemology is, but they do understand the idea. So when I give examples of knowledge structure, I usually give programming examples, cause it's the only field where people know much about the difference between different ways of structuring the same knowledge, and discuss it all the time, and even write books about it. So let's say you want a program to add up 2+2 for you. Now one way you could do this is write a calculator program that can add up any numbers, and also multiply and do other operations. Then it can add up 2+2, but it's also robust, it can add up 3+3, and all sorts of other numbers. It has knowledge in it that lets it apply to lots of questions besides just 2+2. Now suppose you wrote this program:

print 2+2

It's a lot more fragile. When you want to add 3+3, you need to write a new program. This old one is no good. It can't solve any other problems except 2+2. It's not adaptable to other situations except the exact one its designed for. So it's just like studying only for the test tomorrow, and what you learn isn't adaptable to any other situations. Of course, this fragile program is really easy to write, so sometimes it's good enough. The point isn't the fragile way is always worse. But it's different, and it is *fragile*, and it's a good thing to be aware of. And for a lot of people, most of their knowledge of the world is fragile, and that's a big problem! Some people never create much robust knowledge, and that's sad.

There are many common myths about Godwin. One is that he was a socialist (or even a communist). Another that he was a revolutionary (actually there is an anti-revolutions chapter in Political Justice). Another that he was an opponent of Burke (actually he praised Burke several times). Here is one of the more offensive myths:

A Conflict of Visions by Thomas Sowell, p. 28

Thomas Paine's equally polemical reply, The Rights of Man (1791), anticipated in many ways the more systematic unfolding of the unconstrained vision by Godwin two years later [in Political Justice].

Paine's book is in favor of violence, which Godwin detested, and is fully unserious and hateful. The quality of argument is extremely low. Paine simply did not understand Burke's arguments, and so replied with insults and vague utopian grandeur. Godwin, who appreciated Burke and tradition both, and wrote serious and thoughtful arguments, was nothing like Paine.

I don't think Sowell believes this myth due to a political bias. When he says "equally polemical" the other book in question is _Reflections on the Revolution in France_ by Edmund Burke. That is a horrible libel directed at Burke, who Sowell considers a conservative like himself. In fact, Burke's book was not a polemic, and is not comparable to Paine's. Burke wrote a thoughtful, well-argued, objective, serious, and fair book.

Popper was very interested in how athens became so great. his first explanation was culture clash. people like xenophanes and pythagoras came and brought with them different ideas, and this led to questioning conventions and fruitful disagreements. but he did not think this was a full explanation.

today i found out another part of the story, which Popper worked out late in life. it is that Pisistratus (a tyrant of athens) had homer written down as books. before that, homer was an oral tradition, and books were individual things guarded by priests. well, homer got written down in lots of copies, and athens became literate, and everyone read it. then private individuals had some other poetry written down, and sold it, and that was popular too. this paved the way for people to write books for the purpose of commercial publication (the first being, Popper thinks, _On Nature_ by Anaxagoras). and so Athens had the first *book market*, where many books could be purchased cheaply. this also led to competition among writers to make better books.

Popper mentions a nice confirming fact. He found records of large shipments of papyrus from egypt to athens, starting in a year when Pisistratus was in power. he also found several mentions of the book market in surviving books from the time.

You can find this theory in _In Search of a Better World_. look for the chapter title mentioning books *and* the one after it.

_In Search of a Better World_ by Karl Popper, p. 109

When two or more different cultures come into contact, people realize that their ways and manners, so long taken for granted, are not 'natural', not the only possible ones, neither decreed by the gods nor part of human nature. They discover that their culture is the work of men and their history. It thus opens a world of new possibilities: it opens the windows and it lets in fresh air. This is a kind of sociological law, and it explains a lot. And it certainly played an important role in Greek history.

_The Meaning of It All_ pp. 114-115

Who are the witch doctors [of today]? Psychoanalysts and psychiatrists, of course. If you look at all of the complicated ideas that they have developed in an infinitesimal amount of time, if you compare to any other of the sciences how long it takes to get one idea after the other, if you consider all the structures and inventions and complicated things, the ids and the egos, the tensions and the forces, and the pushes and the pulls, I tell you they can't all be there. It's too much for one brain or a few brains to have cooked up in such a short amount of time.

_In Search of a Better World_ by Karl Popper, p 87

Most philosophers are incapable of recognizing either a problem or a solution, even when they are staring them in the face: these things simply lie outside their field of interest.

_In Search of a Better World_ by Karl Popper, p 86

modern left-wing nonsense is generally even worse than modern right-wing nonsense.

The Use of Knowledge in Society by F A Hayek is a good essay. This quote is especially nice:

http://www.econlib.org/library/Essays/hykKnw1.html

One reason why economists are increasingly apt to forget about the constant small changes which make up the whole economic picture is probably their growing preoccupation with statistical aggregates, which show a very much greater stability than the movements of the detail. The comparative stability of the aggregates cannot, however, be accounted for—as the statisticians occasionally seem to be inclined to do—by the "law of large numbers" or the mutual compensation of random changes. The number of elements with which we have to deal is not large enough for such accidental forces to produce stability. The continuous flow of goods and services is maintained by constant deliberate adjustments, by new dispositions made every day in the light of circumstances not known the day before, by B stepping in at once when A fails to deliver. Even the large and highly mechanized plant keeps going largely because of an environment upon which it can draw for all sorts of unexpected needs; tiles for its roof, stationery for its forms, and all the thousand and one kinds of equipment in which it cannot be self-contained and which the plans for the operation of the plant require to be readily available in the market.