Here's the new thread for posting quotes, with the usual rules:
The categories and classes we construct are simply the semantic sugar which makes the reality go down easier. They should never get confused for the reality that is, the reality which we perceive but darkly and with biased lenses. The hyper-relativists and subjectivists who are moderately fashionable in some humane studies today are correct to point out that science is a human construction and endeavor. Where they go wrong is that they are often ignorant of the fact that the orderliness of many facets of nature is such that even human ignorance and stupidity can be overcome with adherence to particular methods and institutional checks and balances. The predictive power of modern science, giving rise to modern engineering, is the proof of its validity. No talk or argumentation is needed. Boot up your computer. Drive your car.
...Two very different attitudes toward the technical workings of mathematics are found in the literature. Already in 1761, Leonhard Euler complained about isolated results which "are not based on a systematic method" and therefore whose "inner grounds seem to be hidden." Yet in the 20'th Century, writers as diverse in viewpoint as Feller and de Finetti are agreed in considering computation of a result by direct application of the systematic rules of probability theory as dull and unimaginative, and revel in the finding of some isolated clever trick by which one can see the answer to a problem without any calculation.
[...]
Feller's perception was so keen that in virtually every problem he was able to see a clever trick; and then gave only the clever trick. So his readers get the impression that:
- Probability theory has no systematic methods; it is a collection of isolated, unrelated clever tricks, each of which works on one problem but not on the next one.
- Feller was possessed of superhuman cleverness.
- Only a person with such cleverness can hope to find new useful results in probability theory.
Indeed, clever tricks do have an aesthetic quality that we all appre
I recall a math teacher in high school explaining that often, in the course of doing a proof, one simply gets stuck and doesn't know where to go next, and a good thing to do at that point is to switch to working backwards from the conclusion in the general direction of the premise; sometimes the two paths can be made to meet in the middle. Usually this results in a step the two paths join involving doing something completely mystifying, like dividing both sides of an equation by the square root of .78pi.
"Of course, someone is bound to ask why you did that," he continued. "So you look at them completely deadpan and reply 'Isn't it obvious?'"
I have forgotten everything I learned in that class. I remember that anecdote, though.
One of the characteristics of successful scientists is having courage. Once you get your courage up and believe that you can do important problems, then you can. If you think you can't, almost surely you are not going to. Courage is one of the things that Shannon had supremely. You have only to think of his major theorem. He wants to create a method of coding, but he doesn't know what to do so he makes a random code. Then he is stuck. And then he asks the impossible question, ``What would the average random code do?'' He then proves that the average code is arbitrarily good, and that therefore there must be at least one good code. Who but a man of infinite courage could have dared to think those thoughts? That is the characteristic of great scientists; they have courage. They will go forward under incredible circumstances; they think and continue to think.
Note that xkcd 759 is about something subtly different: you work from both ends and then, when they don't meet in the middle, try to write the "solution" in such a way that whoever's marking it won't notice the jump.
I know someone who did that in an International Mathematical Olympiad. (He used an advanced variant of the technique, where you arrange for the jump to occur between two pages of your solution.) He got 6/7 for that solution, and the mark he lost was for something else. (Which was in fact correct, but you will appreciate that no one was inclined to complain about it.)
Then there is the famous fly puzzle. Two bicyclists start twenty miles apart and head toward each other, each going at a steady rate of 10 m.p.h. At the same time a fly that travels at a steady 15 m.p.h. starts from the front wheel of the southbound bicycle and flies to the front wheel of the northbound one, then turns around and flies to the front wheel of the southbound one again, and continues in this manner till he is crushed between the two front wheels. Question: what total distance did the fly cover ?
The slow way to find the answer is to calculate what distance the fly covers on the first, northbound, leg of the trip, then on the second, southbound, leg, then on the third, etc., etc., and, finally, to sum the infinite series so obtained. The quick way is to observe that the bicycles meet exactly one hour after their start, so that the fly had just an hour for his travels; the answer must therefore be 15 miles.
When the question was put to von Neumann, he solved it in an instant, and thereby disappointed the questioner: "Oh, you must have heard the trick before!"
"What trick?" asked von Neumann; "all I did was sum the infinite series."
An anecdote concerning von Neumann, here told by Halmos.
Related.
I really wish we had brain scans of this guy at 19 and at 25. I want to see which areas were developed!
Making a feelings happen directly isn't easy. It's a skill. Given the demographic on this website there a good chance that a lot of the readers can't control their feelings. Most of the people here are skilled at rationality but not that skilled at emotional matters.
It's a bad idea to generalise your own inability to control your feelings to other people.
Directly is a tricky word. In some sense you aren't doing things directly when you follow a step by step process.
If you however want a step by step process I can give it to you (but please don't complain that it's not direct enough):
1) You decide which emotion you want to feel.
2) You search in your mind for an experience when you felt the emotion in the past.
3) You visualize the experience.
4) In case that you see yourself inside your mental image, see the image as if you are seeing it through your own eyes.
5) If the image is black and white, make it colored.
6) Make the image bigger.
7) Locate the emotion inside your body.
8) Increase the size of the emotion.
9) Get it moving.
10) Give it a color.
11) Increase movement and size as long as you want.
That's the way of doing it I learned at day two of an NLP seminar.
...So, let's say some bros of mine and I have some hand-signals for, you know, bro stuff. And one of the signals means, "Oh, shit. Here comes that girl! You know. That girl. She's coming." That signal has a particular context. Eventually, one of my bros gets tired of sloppy use of the signal, and sets about laying out specifically what situations make a girl that girl. If I used the signal in a close-but-not-quite context, he'd handle it and then pull me aside and say, "I know she and I had that thing that one time, but we never... well, it wasn't quite THAT. You know? So that signal, it freaked me out, because I thought it had to be someone else. Make sure you're using it properly, okay?" And I'd be like, "Bro. Got it."
Another friend of mine, he recognizes the sorts of situations we use the signal in have a common thread, so he begins using the hand signal for other situations, any situation that has the potential for both danger and excitement. So if someone invites us to this real sketchy bar, he'll give me the signal - "This could be bad. But what if it's not?" And I'd respond, "I see what you did there."
Maybe you see where this
And clearly my children will never get any taller, because there is no statistically-significant difference in their height from one day to the next.
Andrew Vickers, What Is A P-Value, Anyway?
Do you ever get the feeling that God has a plan?
And you're the only one who can stop it?
When I was 11, I was fascinated with a flame and I didn't know what it was. I went to a teacher and said, "What's a flame? What's going on in there?" And she said "It's oxidation." And that's all she said. And I never heard that word before, so that was like, calling it by another name.
--Alan Alda, in an interview at The Colbert Report, telling the story that gave rise to The Flame Challenge. It has been mentioned on LW before, but I thought it was worth posting it here as a perfect illustration of a Teacher's Password.
[About the challenge of skeptics to spread their ideas in society] In times of war we need warriors, but this isn't war. You might try to say it is, but it's not a war. We aren't trying to kill an enemy. We are trying to persuade other humans. And in times like that we don't need warriors. What we need are diplomats.
Phil Plait, Don't Be A Dick (around 23:30)
I am reminded of a commentary on logic puzzles of a certain kind; it was perhaps in a letter to Martin Gardner, reprinted in one of his books. The puzzles are those about getting about on an island where each native either always tells the truth or always lies. You reach a fork in the road, for example, and a native is standing there, and you want to learn from him, with one question, which way leads to the village. The “correct” question is “If I asked you if the left way led to the village, would you say yes?” But why should the native’s concept of lying conform to our own logical ideas? If the native is a liar, it means he wants to fool you, and your logical trickery will not work. The best you can do is say something like “Did you hear they are giving away free beer in the village today?” and see which way the native runs. You follow him, even if he says something like “Ugh, I hate beer!” since then he probably really is lying.
In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time someting like that happened in politics or religion.
-- Carl Sagan, 1987 CSICOP Keynote Address
I don't think that the idea that politicians don't change their position has much basis in reality. There are a lot of people who complain about politicians flip-flopping.
When a politician speaks publically, he usually doesn't speak about his personal decision but about a position that's a consensus of the group for which the politician speaks. He might personally disagree with the position and try to change the consensus internally. It's still his role to be responsible for the position of the group to which he belongs. In the end the voter cares about what the group of politicians do. What laws do they enact? Those laws are compromises and the politicians stand for the compromise even when they personally disagree with parts of it.
A scientist isn't supposed to be responsible for the way his experiments turn out.
And if you take something like the Second Vatican Council there's even change of positions in religion.
“My other piece of advice, Copperfield,” said Mr. Micawber, “you know. Annual income twenty pounds, annual expenditure nineteen nineteen six, result happiness. Annual income twenty pounds, annual expenditure twenty pounds ought and six, result misery."
Charles Dickens, David Copperfield (HT Cafe Hayek.)
A reasonable start, but quite insufficient for the long run. Sixpence savings on twenty pounds income is not going to insulate you from disaster, not even with nineteenth-century money.
If you pay nothing for expert advise you will value it at epsilon more than nothing, if you pay five figures for it you will clear your schedule and implement recommendations within the day. In addition to this being one of consulting’s worst-kept secrets, it suggests persuasive reasons why you should probably extract a commitment out of software customers prior to giving them access for the software. Doing this will automatically make people value your software more
Patrick McKenzie, the guy who gets instrumental rationality on the gut level.
More from the same source:
...I always thought I really hated getting email. It turns out that I was not a good reporter of my own actual behavior, which is something you’ll hear quite a bit if you follow psychological research. (For example, something like 75% of Americans will report they voted for President Obama, which disagrees quite a bit with the ballot box. They do this partially because they misremember their own behavior and partially because they like to been seen as the type of person who voted for the winner. 99% of geeks will report never having bought anything as a result of an email. They do this because they misremembe
If you pay nothing for expert advise you will value it at epsilon more than nothing, if you pay five figures for it you will clear your schedule and implement recommendations within the day.
Obviously I need to figure out how to start charging for my website!
I've had the impression that you've been selling yourself short for quite some time.
Maybe you can start by following Patrick's example and offering some of the choice data you collect and analyze to the people subscribing to your mailing list. You can also figure out who might be interested in the information you collect (a cool project in itself), and how much it would be worth to them.
The present impossibility of giving a scientific explanation is no proof that there is no scientific explanation. The unexplained is not to be identified with the unexplainable, and the strange and extraordinary nature of a fact is not a justification for attributing it to powers above nature.
I suspect that if the source was a less unexpected one, say Albert Einstein or Carl Sagan, the quote would seem obvious and uninteresting to LWers and its karma score would be less than half what it is.
I was not surprised by this, because I know many Catholics honestly try to be rational... of course only within the limits given by the Church.
They would have absolutely no problem with Bayesian updating; the only problem would be the Solomonoff prior. If you replace it by "the Catholic Church is always right" prior, you are free to update rationally on everything else and remain a good Catholic.
This is why Catholics don't have a problem to accept e.g. evolution, as long as someone can provide an explanation how evolution can be compatible with "the Catholic Church is always right". (A possible explanation could be e.g. that God created the first life forms; that evolution is a consequence of physical laws created by God, therefore any result of evolution is still indirectly created by God; and that humans are somehow an exception to this process, because even if their bodies are a result of evolution, they also have an immaterial soul created directly by God.)
People who do great things look at the same world everyone else does, but notice some odd detail that's compellingly mysterious.
Paul Graham, What You'll Wish You'd Known
Bit of a tangent, but something from that essay always bothered me.
I recently saw an ad for waiters saying they wanted people with a "passion for service." The real thing is not something one could have for waiting on tables.
Paul Graham
...So I began to linger in my duties around Vincent's tables to observe his technique. I quickly learned that his style was to have no single style. He had a repertoire of approaches, each ready to be used under the appropriate circumstances. When the customers were a family, he was effervescent—even slightly clownish— directing his remarks as often to the children as the adults. With a young couple on a date, he became formal and a bit imperious in an attempt to intimidate the young man (to whom he spoke exclusively) into ordering and tipping lavishly. With an older, married couple, he retained the formality but dropped the superior air in favor of a respectful orientation to both members of the couple. Should the patron be dining alone, Vincent selected a friendly demeanor—cordial, conversational, and warm. Vincent reserved the trick of seeming to argue against his own interests for large parties of 8 to 12 people. His technique was ve
It doesn't seem to me that Vincent-as-described-by-Cialdini is someone with a passion for waiting at tables; especially not the sort that could also be described as a "passion for service". If anything, he has a passion for exploiting customers, or something of the kind. I would expect someone with a genuine passion for table-waiting -- should such a person exist -- to be as reluctant to mislead customers as, say, someone with a passion for science would be to spend their life working for a partisan think tank putting out deliberately misleading white papers on controversial topics.
(To forestall political arguments: I am not implying that all think tanks are partisan, nor that all white papers put out by partisan think tanks are deliberately misleading.)
The biggest threat to an artist is neither piracy nor obscurity. It's dicking around on the internet.
Humility bids us to take ourselves as we are; we do not have to be cosmically significant to be genuinely significant.
One reason why research is so important is precisely that it can surprise you and tell you that your subjective convictions are wrong. If research always found what we expected, there wouldn't be much point in doing research.
--Eugene Gendlin
Seek not to follow in the footsteps of men of old; seek what they sought. -Matsuo Basho, poet (1644-1694)
Seems like a good way to think of the "seek to succeed, not to be rational" idea.
[...] if you make yourself really small you can externalize virtually everything. The imaginative pressure to think of yourself as very small is easy enough to find. When I raise my arm, well what is it? There must be some part of my brain that is sort of sending out the signal and then my arm is obeying me, and then when I think about the reasons why, it’s very natural to suppose that my reason store is over there somewhere, and I asked my reason store to send me some good reasons. So the imagery keeps shrinking back to a singularity; a point, a sort of Cartesian point at the intersection of two lines and that’s where I am. That’s the deadly error, to retreat into the punctate self. You’ve got to make yourself big; really big."
Aren't Graham and Dennett talking about different things entirely? Dennett is trying to help us understand better how materialism is compatible with having free will and a conscious self; his prescription here is to avoid a common pitfall, that of dismissing all "upwards" processing of perception and all "downwards" action-starting signals as "mechanical computing, not part of the self" and locating the Cartesian self at the zero-extension intersection of these two processes. It is better to think of the self as extended in both directions. When Graham says "keep your identity small", he is talking about a different sense of "identity" and "small", roughly "do not describe yourself with labels because you might become overly invested in them and lose objectivity and perspective".
"The veil before my eyes dropped. I saw he was insincere ... a liar. I saw marriage with him would have been marriage to a worthless adventurer. I saw all this within five minutes of that meeting.” As if she heard a self-recriminatory bitterness creep into her voice again, she stopped; then continued in a lower tone. “You may wonder how I had not seen it before. I believe I had. But to see something is not the same as to acknowledge it."
-- John Fowles, The French Lieutenant's Woman
It is better to build a seismograph than to worship the volcano.
-- Terry Pratchett (on Nation)
In the past I have made an analogy between science and the Roman Catholic Church, despite the discomfort of some readers. I go back to that now. The Catholic Church of the years during which Erasmus flourished was quite corrupt. It is upon this fertile ground that the printing press added some combustible fuel. But despite his influence upon them Erasmus could never be convinced by the Reformers to leave the Church. Why? Erasmus was a critic of the Church, but he also perceived in it a superior product to what Protestantism had on offer. At any given moment science is rather like the Catholic Church, riddled with falsehood. But it is the best we have, and we should attempt to work within its institutional framework, rather tearing it apart limb from limb. That was Erasmus’ position. He may have been a critic, but ultimately he thought the institution could be genuinely reformed. The struggle never ends, but we can’t see any returns if we give up immediately.
--Razib Khan, The Erasmus Path in Science
In the mathematics I can report no deficience, except that it be that men do not sufficiently understand the excellent use of the pure mathematics, in that they do remedy and cure many defects in the wit and faculties intellectual. For if the wit be too dull, they sharpen it; if too wandering, they fix it; if too inherent in the sense, they abstract it. So that as tennis is a game of no use in itself, but of great use in respect it maketh a quick eye and a body ready to put itself into all postures; so in the mathematics, that use which is collateral and intervenient is no less worthy than that which is principal and intended.
"But say an assembled force of divine beings had teamed up and got everybody to evacuate the coasts.”
“Yeah, say they did,” I said. “Where’s the downside?”
“Maybe there isn’t one,” Steff said. “But if they’re doing that, what about all the people who died from fires or plagues or war or basic stupidity at the same time?”
“I don’t know,” I said. “Maybe the gods should just a more pro-active stance on that stuff anyway.”
“Okay, but… where does it stop?”
“Maybe it stops when everybody’s safe!” I said...
(I read it for the worldbuilding...)
Indeed the authority of those who profess to teach is often a positive hindrance to those who desire to learn; they cease to employ their own judgement, and take what they perceive to be the verdict of their chosen master as settling the question. In fact I am not disposed to approve the practice traditionally ascribed to the Pythagoreans, who, when questioned as to the grounds of any assertion that they advanced in debate, are said to have been accustomed to reply 'He himself said so', 'he himself' being Pythagoras. So potent was an opinion already decided, making authority prevail unsupported by reason.
Cicero, De Natura Deorum
Any intelligent fool can make things bigger and more complex... It takes a touch of genius - and a lot of courage to move in the opposite direction.
-- Albert Einstein
...There was a time in my life when I couldn't get anything done. ...
Perfectionism, which was always a friend, turned into my worst enemy. ...
I've heard that "perfect is the enemy of good enough" many times, but the repressed artist in me refused to accept this as truth. ...
Eventually I lucked out. By accident (or was it an accident?) I stumbled on the fascinating Book of Tea which led me to the concept of Wabi-sabi - the Japanese art of imperfect beauty. ...
Looking at Wabi-sabi objects was a breath of fresh air. Inability to achieve any lasting pe
Margaret Fuller, intoxicated by Transcendentalism, said, "I accept the universe," and Thomas Carlyle, told of the remark, supposedly said, "Gad, she’d better."
If we find out tomorrow that the universe is made of jello, all we will have learned about morality is that it, like everything else, is ultimately jello-dependent.
There is a condition worse than blindness, and that is seeing something that isn't there.
Thomas Hardy
Any muttonhead with money can have a nice house or car or airplane, but how many can build one?
Dean Ing, The Ransom of Black Stealth One
Exactly. Buying things is far more practical, harnessing the power of specialization and comparative advantage. Building the thing yourself is almost always the incorrect decision. Build it yourself if you are good at building that kind of thing and, more importantly, suck at doing other things that provide more (fungible) value.
The presupposition is that passing judgment on somebody’s “lifestyle” (for those who do not speak psychobabble, this means the English word behaviors) is an activity which is forbidden. It follows immediately that when the person says to you “Don’t be all judgmental” they are in fact passing judgment on your behavior. In other words, they are “being all judgmental.” It is, therefore, impossible not to pass judgment. I do not mean “impossible” in the colloquial sense of “unlikely”, but in the logical sense of “certainly cannot be no matter what.”
I am a Norman. It is the immemorial custom of my people to conquer our neighbours, seize their land, suppress their culture, and impose our rule as aristocrats. By the principle of cultural relativity this way of life is no worse than any other.
Brett Evill
The best similar cultural-relativity-based deduction I've read, as introduced by Wikipedia:
A story for which [Charles James] Napier is often noted involved Hindu priests complaining to him about the prohibition of Sati by British authorities. This was the custom of burning a widow alive on the funeral pyre of her husband. As first recounted by his brother William, he replied:
"Be it so. This burning of widows is your custom; prepare the funeral pile. But my nation has also a custom. When men burn women alive we hang them, and confiscate all their property. My carpenters shall therefore erect gibbets on which to hang all concerned when the widow is consumed. Let us all act according to national customs."
most people only condone violence against those who break the anti-violence norm
Most people condone violence for a lot more reasons than that.
Nothing in life is to be feared, it is only to be understood. Now is the time to understand more, so that we may fear less.
--Marie Curie
Understand that your system will resist change: Good ideas are not adopted automatically. They must be driven into practice with courageous patience -- Admiral Rickover
...The Western World has been brainwashed by Aristotle for the last 2,500 years. The unconscious, not quite articulate, belief of most Occidentals is that there is one map which adequately represents reality. By sheer good luck, every Occidental thinks he or she has the map that fits. Guerrilla ontology, to me, involves shaking up that certainty.
I use what in modern physics is called the "multi-model" approach, which is the idea that there is more than one model to cover a given set of facts. As I've said, novel writing involves learning to think l
"Rich people plan for three generations. Poor people plan for Saturday night." -- Gloria Steinem
For instance, becoming intellectually convinced that sexual jealousy is a bad idea does not purge you of experiencing any.
Here, we report that colonization by gut microbiota impacts mammalian brain development and subsequent adult behavior. Using measures of motor activity and anxiety-like behavior, we demonstrate that germ free (GF) mice display increased motor activity and reduced anxiety, compared with specific pathogen free (SPF) mice with a normal gut micro- biota. ... Hence, our results suggest that the microbial colonization process initiates signaling mechanisms that affect neuronal circuits involved in motor control and anxiety behavior.
It's interesting, all right, but I think it would likely be better received as a standalone Discussion post (ideally with some more context and expansion). The rationality quotes threads tend to be more for quotes directly about rationality or bias than quotes indirectly contributing to our potential understanding of the same.
On lost purposes:
...The therapy changed my life. It feels as if I added a new sense to my palate of senses. I feel as if I was color blind for many years and at last I can see every color. Now that I’ve learned to recognize my pain, I can do something about it. I am so much happier today than I ever was before. While my friends may not have consciously recognized the big change in me, they have stopped calling me clueless and now often come to me for advice.
Did this solve my problem of tiredness? When Ella Friedman told me that I was no longer depressed, I
It was impossible for sure. OK. So, let’s start working.
-Philippe Petit. On the idea of walking rope in between the World Trade Center towers.
You have to know exactly what you want, and you have to know exactly how to get it.
Eben Moglen, on how to change the world
A lot more people have heard of Michael Jordan than have heard of Norman Borlaug. Yet Borlaug is one of the few humans on the planet who can be personally credited with saving millions of lives. Who one has heard of is not likely to be highly correlated with what impact people have had.
One of the defence team of Phil Zimmermann in the PGP case. General counsel of the Free Software Foundation and founder of the Software Freedom Law Center. Mostly responsible for the changes between version 2 and version 3 of the GNU General Public License.
I'm not sure any of that counts as changing the world, but it does seem like he's had some impact.
I love truth. It's such a wonderful thing. It makes you sane, helps you make better, more effective decisions and it irks all the right people. -Aaron Clarey aka "Captain Capitalism"
...There is no evidence to show that man is created and accoutered to serve as God's vice-regent upon the earth. There is no reason to believe that he is naturally good and kind and brave and wise, or ever was. On the contrary, there is much to show that he is a beast, that has taken a strange turning in the jungle and blundered rather aimlessly into a mental world in which he is certainly not at home. [...]
That is his beauty and his significance: that out of the primordial forces of sex and survival he has forged reason and science, and spun the gossamer
What do we mean when we say that first of all we seek liberty? I often wonder whether we do not rest our hopes too much upon constitutions, upon laws, and upon courts. These are false hopes; believe me, these are false hopes. Liberty lies in the hearts of men and women; when it dies there, no constitution, no law, no court can save it; no constitution, no law, no court can even do much to help it. While it lies there, it needs no constitution, no law, no court to save it.
Judge Learned Hand
I like Judge Learned Hand, but I think this particular quote is just Deep Wisdom. Living in a pleasant society requires both good laws and good people. There is very little substantive content in LH's oratory. He could just as easily have made the opposite point:
What does it mean to strive for fairness or impartiality? I often wonder whether we do not rest our hopes too much upon virtue, upon self-discipline, and upon honor. These are false hopes; believe me, these are false hopes. Justice is simply a matter of fair play; when the rules are made to be broken, no amount of personal virtue can keep a man from temptation, and when the rules are honestly followed by one's peers, no special virtue is needed to join them.
Humor is the brain rewarding us for finding errors and inconsistencies in our thinking.
When you choose technology, you have to ignore what other people are doing, and consider only what will work the best. -Paul Graham
Very few people see their own actions as truly evil.... It is left to their victims to decide what is evil and what is not.
Laurell K. Hamilton
A quote I find useful when considering both rationalizing, and the differences of relative perspective.
Whatever doubt or doctrinal Atheism you and your friends may have, don't fall into moral atheism.
-Charles Kingsley
Your knowledge of what is going on can only be superficial and relative.
William S. Burroughs
I don't understand. Are you saying it wasn't impossible enough?
He actually did it in 1974. It took nearly six years of planning. In order to practice for the walk between the World Trade Center towers he first did tightrope walks between the towers of the Notre Dame and then the Sydney Harbor Bridge. All of these were of course illegal. In WTC case, he had to sneak in, tie the ropes between the towers without anyone knowing and walked between the towers without any harness for nearly 45 mins at that height with the wind and everything. For the complete details, watch the documentary 'Man on Wire'. I think it was as impossible as it got in his line of work.
How on earth could you not understand? If this is sincere incomprehension then all I can do is point to google: define.
Yes. This quote is an example of nothing more than how to be confused about words and speak hyperbole for the sake of bravado.
If you have to ask whether something is "impossible enough" you have already answered your question.