Jonathan Swift

Falsehood flies, and the Truth comes limping after it.

R.W. Hamming

I received a new book in the mail today. I'm a huge fan of Richard Hamming (e.g. this), and the book is everything I hoped for.

I thought I would just post a quote (from him, not one of the many interesting quotes he includes):

The taste to work on the right problem at the right time and in the right way is the secret of doing significant things.

To focus on just one aspect: what you are trying to do must be doable. Timing is (almost) everything.

Duly quoted

Recycled from an earlier post:

Programs must be written for people to read, and only incidentally for machines to execute.

- Abelson & Sussman, SICP

How do we convince people that in programming simplicity and clarity—in short: what mathematicians call "elegance"— are not a dispensable luxury, but a crucial matter that decides between success and failure?

- E. W. Dijkstra

High standards

The nice thing about standards is that there are so many to choose from. And if you really don't like all the standards you just have to wait another year until the one arises you are looking for.

-- A. Tanenbaum, "Introduction to Computer Networks", quoted here

Eyes open

link

Duly Quoted

On "overfitted" models:

J.Bertrand said it this way: 'Give me four parameters and I shall describe an elephant; with five, it will wave its trunk.

--L. Le Cam

first page here
behind a firewall, sorry :(
do the jstor thing if you can..

Duly quoted

If a man is offered a fact which goes against his instincts, he will scrutinize it closely, and unless the evidence is overwhelming, he will refuse to believe it. If, on the other hand, he is offered something which affords a reason for acting in accordance to his instincts, he will accept it even on the slightest evidence.

--Bertrand Russell
cited here with many others

Duly quoted: Steven Chu

source

The other issue is that the ideas are complex. Now, if you step back and if you spend some serious time thinking about it, the kernel of the ideas are clearly not complex. The essence of an idea is what we try to work with most. As a professor with my graduate students, we would read a paper and look at the paper and say, "What's the essence of the idea? What's something new? Forget about the equations. Forget about the complicated argument and try to identify the kernel of the idea."

--Steven Chu

Lucretius speaks to us of atoms

Clothes hung above a surf-swept shore grow damp; spread in the sun they dry again. Yet it is not apparent to us how the moisture clings to the cloth, or flees the heat. Water, then, is dispersed in particles, atoms too small to be observable.
..
For surely the atoms did not hold council assigning order to each, flexing their keen minds with questions of place and motion and who goes where. But shuffled and jumbled in many ways, in the course of endless time they are buffeted, driven along, chancing upon all motions, combinations. At last they fall into such an arrangement as would create this universe..

-Lucretius (De rerum natura)
as quoted by David Lindley in Boltzmann's Atom

On the value of silicon

Computers are no more a threat to mathematicians than food
processors are a threat to cooks.

Andrei Okounkov as quoted here

Duly quoted

I have always imagined that paradise will be a kind of library.

--- Jorge Luis Borges

Sighted on AbeBooks---a favorite site. info on source

Comparing apples and oranges?

I have a post about Newton's brilliant insight that gravity as observed on earth could be extended to the moon. You can read about this lots of places, I like James Gleick's Isaac Newton (Amazon).

Many years later Newton told at least four people that he had been inspired by an apple in his Woolsthorpe garden--perhaps an apple actually falling from a tree, perhaps not. He never wrote of an apple. He recalled only:

I began to think of gravity extending to the orb of the Moon . . .

---gravity as a force, then, with an extended field of influence; no cutoff or boundary---

& computed the force requisite to kep the Moon in her Orb with the force of gravity at the surface of the earth . . . & found them answer pretty nearly. All this was in the two plague years of 1665-1666. For in those days I was in the prime of my age for invention & minded mathematicks and Philosophy more than at any time since.

The apple was nothing in itself. It was half of a couple---the moon's impish twin. As an apple falls toward the earth, so does the moon; falling away from a straight line, falling around the earth.

---Gleick
Isaac Newton (p. 55)

The force acting on the moon or the apple is proportional to the mass for each, but the acceleration imparted is in turn proportional to that force divided by the mass, which cancels the mass term (for apple and moon).

This leaves an equation relating the acceleration to a constant (G) times the mass of the earth (M) divided by the square of the distance to earth. Thus, we expect that the acceleration (and the distance moved) for the moon and the apple to be in the inverse ratio as the square of their distance from the earth.

a = GM/r2

The key relationship is shown in the diagram.

We draw the tangent to the orbital circle at time-zero at a right angle with the radius. Then the distance moved in one second, s, is the velocity times the time. The hypotenuse, H, is calculated from R and s by the Pythoagorean Theorem. And the distance "fallen" in the direction of the earth is the difference between H and the radius, R.

R = EM distance H = sqrt (R2 + (radial velocity * 1 sec)2) d = H - R

d is very small compared to R and H, but it still works. Using modern values for the distances:

mean distance from E to M (km) R (km) = 3.84x105 (range 3.63-4.06) circumference of M orbit = 2π 3.84x105 km mean radius of E (km) = 6.37x103 (range 6.36-6.38) ratio (EM dist/E radius) = 60.3 ratio2 = 3636 period of orbit of M T = 27.32 d = 2.36x106 seconds radial velocity of M C/T = 1.022 km/sec H = sqrt((3.84x105)2 + (1.022)2) = 384000.00000136002 M falls in 1 sec = 1.36 mm earth surface gravity = 9.8 m/s2 you fall in 1 sec = 1/2 g t2 = 4.9 m ratio = 4900 / 1.36 = 3603

I read somewhere that Newton first did this calculation with a value for the moon's orbital radius that was sufficiently off for him to think his result did not agree with it. Later he repeated his calculation with a more accurate value. But I can't find it now. One of these days I have to get a copy of the Principia (Amazon).

Duly quoted

One day the parts of the body argued about who ought to be the boss.

The brain said, “I do the thinking around here, so I should be in charge.”
The hands said, “We do all the work around here, so we ought to be in charge.”
The feet said, “If we didn’t carry the body around, nothing could get done, so we ought to be in charge.”

Every part of the body made its claim, until finally the rectum piped up, “I want to be in charge!”

read the rest
--Mark Kleiman

Duly quoted

Randall Munroe (of xkcd) in a Google talk:

If Python is "executable pseudocode",
then Perl is "executable line noise."

Now be nice...

Duly quoted

I don't know about you, but I buy a lot of books. There is a quote attributed to Erasmus, "First I buy books...then clothes." Luckily I don't have to choose.

Typically these days the way I buy books is that I use Amazon, and put books in my shopping cart, then go back periodically and change their order, based on (for example) the "Surprise me" feature. It's a kind of bubble selection sort. And it really surprises me how many publishers have disabled or even just crippled this feature. You think I don't notice when the pages aren't sampled randomly? It always suggests to me that they're worried that I wouldn't buy the book if I had it in my hand.

So I'm thinking about this book about Einstein. And there's a wonderful quote in there, from one of my very favorite books: "The Ascent of Man," by Jacob Bronowski. Do yourself a favor and find a copy of that. It is exquisite. Here's the quote:

It is almost impertinent to talk of the ascent of man in the presence of two men, Newton and Einstein, who stride like gods. Of the two, Newton is the Old Testament god; it is Einstein who is the New Testament figure. He was full of humanity, pity, a sense of enormous sympathy. His vision of nature herself was that of a human being in the presence of something god-like, and that is what he always said about nature. He was fond of talking about God: "God does not play dice," "God is not malicious." Finally Niels Bohr one day said to him, "Stop telling God what to do." But that is not quite fair. Einstein was a man who could ask immensely simple questions. And what his life showed, and his works, is that when the answers are simple too, then you hear God Thinking.

Do yourself another favor and find a copy of the video of the (1974) BBC series. It's fantastic.

Duly quoted

Some nice quotes on ideas
(from the numpy handbook; download, and one from Stroustrup)

Don’t worry about people stealing your ideas. If your ideas are any good, you’ll have to ram them down people’s throats.

—Howard Aiken, IBM engineer

No idea is so antiquated that it was not once modern; no idea is so modern that it will not someday be antiquated.

—Ellen Glasgow

Language shapes the way we think, and determines what we can think about.

—B. L. Whorf

Duly quoted

I found a thread discussing Python versus R. If you, like me, have used both R and Python, I think you'll find it interesting. My favorite quote:

The difference between a general purpose language and a DSL is the difference between a cow and a carton of milk. Sure, the cow has lots more features - it can make lots more milk and fertalizer to boot, and it can even pull a wagon if you are so inclined. But if all you want is a glass of milk and you get a cow, then you've got an oversized bovine crapping in your office.

Duly quoted

Cargo cult science

I mentioned this the other day, but it deserves its own post:

During the war they saw airplanes land with lots of good materials, and they want the same thing to happen now. So, they've arranged to make things like runways, to put fires along the sides of the runways, to make a wooden hut for the man to sit in, with two wooden pieces on his head like headphones and bars of bamboo sticking out like antennas---he's the controller---and they wait for the airplanes to land. They're doing everything right. The form is perfect. It looks exactly the way it looked before. But it doesn't work. No airplanes land. So I call these things cargo cult science ...

---Richard Feynman in Surely You're Joking, Mr. Feynman

Duly quoted

On the value of experience...

As the saying goes ... Frederick the Great's horse was on seven campaigns, but at the end of it all he was still a horse."

quoted by Tom Ricks

Duly Quoted

Here's a funny (and telling) story about a job interview someone had with Johnny von Neumann (and my post here):

"Von Neumann lived in this elegant lodge house on Westcott Road in Princeton... As I parked my car and walked in, there was this very large Great Dane dog bouncing around on the front lawn. I knocked on the door and von Neumann, who was a small, quiet, modest kind of a man, came to the door and bowed to me and said, 'Bigelow, won't you come in,' and so forth, and this dog brushed between our legs and went into the living room. He proceeded to lie down on the rug in front of everybody, and we had the entire interview---whether I would come, what I knew, what the job was going to be like---and this lasted maybe forty minutes, with the dog wandering all around the house. Towards the end of it, von Neumann asked me if I always traveled with the dog. But of course it wasn't my dog, and it wasn't his either, but von Neumann---being a diplomatic, middle-European type person---he kindly avoided mentioning it until the end."

--Julian Bigelow
quoted in:
Who got Einstein's Office
Ed Regis
p 110