davidad

"This business has changed. There are no phones anymore. There are simply things that also phone."

Mon, 08 Mar 2010 11:28:34 -0500

“This business has changed. There are no phones anymore. There are simply things that also phone.”

- Gizmodo’s critique of Sony

It's a real-life heist!

Mon, 08 Mar 2010 09:33:44 -0500

It's a real-life heist!:

Is it wrong that I think it’s kind of awesome that some people actually pulled this off? >_>

OK Go has the best music videos of ALL TIME (see also the...

Mon, 08 Mar 2010 09:31:50 -0500

OK Go has the best music videos of ALL TIME

(see also the marching band version)

"The Mad Hatter and the March Hare champion the mathematics of William Rowan Hamilton, one of the..."

Mon, 08 Mar 2010 01:37:10 -0500

“The Mad Hatter and the March Hare champion the mathematics of William Rowan Hamilton, one of the great innovators in Victorian algebra. Hamilton decided that manipulations of numbers like adding and subtracting should be thought of as steps in what he called “pure time.” This was a Kantian notion that had more to do with sequence than with real time, and it seems to have captivated Dodgson. In the title of Chapter 7, “A Mad Tea-Party,” we should read tea-party as t-party, with t being the mathematical symbol for time.”

- an unorthdox interpretation of Alice in Wonderland as a metaphor for counterintuitive mathematics

Dude. It’s SET, Scrabble, and Yahtzee all in one.

Thu, 04 Mar 2010 18:21:17 -0500

Dude. It’s SET, Scrabble, and Yahtzee all in one.

Is this art?...and why that's the wrong question.

Thu, 04 Mar 2010 17:37:05 -0500

Is this art?...and why that's the wrong question.:

(by Julia Galef)

"Perhaps there are people who don’t think visually…who imagine things - but they should..."

Wed, 03 Mar 2010 20:34:08 -0500

“Perhaps there are people who don’t think visually…who imagine things - but they should have another word, because ‘imagine’ has ‘image’ hidden in it.”

- Marvin Minsky

"The philosophers have convinced the world that the important thing about quantum theory is..."

Wed, 03 Mar 2010 19:52:47 -0500

“The philosophers have convinced the world that the important thing about quantum theory is uncertainty[…]but quantization is what makes determinism practical[…]I might have got that idea from arguing with Feynman.”

- Marvin Minsky

E15 lobby at dusk

Wed, 03 Mar 2010 00:13:02 -0500

E15 lobby at dusk

We interrupt your regularly scheduled philosophical rant to...

Tue, 02 Mar 2010 10:38:12 -0500

We interrupt your regularly scheduled philosophical rant to bring you this lolcat, which presents a rather poor pun relying on the knowledge of an obscure philosophical term.

Enjoy!

Why is our universe here?

Tue, 02 Mar 2010 04:55:00 -0500

(Sorry, faithful readers, but I’m simply in a philosophical mood lately!)

This is one of the classic questions in philosophy: Why are we here? Or, adding evolution to the picture: Why is our universe here?

My standard response to this sort of question is a strong form of the anthropic principle, combined with an appeal to the notion that all logically consistent universes may lay the same claim to existence, which is (at least to me) much more intuitively reasonable than the notion that our universe is the only one, and we’re awfully lucky that it isn’t a game of Tic-Tac-Toe instead of the four-dimensional curved spacetime that it is, thus allowing the materialistic diversity for an intelligent species to someday evolve. We’re not “lucky,” this is simply the only universe of infinitely many in which we naturally evolved, so here is where we are.

But I have recently discovered a fundamental flaw in this position which presses me to re-evaluate it. The necessity of a habitable planet, suitable molecular dynamics for cells and brains, etc., does not adequately explain, for instance, why there are so many stars around. Would not a single sun, with a single Earth, be enough for life to evolve? Why all this junk? Ockham’s razor would suggest it would not be likely to appear at all, let alone in the vast quantities it does.

To resolve this, I must amend my egalitarianism towards universes. Perhaps the “degree of existence,” or the likelihood that a given universe exists, is dependent on the number of bits necessary to specify it - the a priori information content that must be granted to such a universe before we can begin to derive what might happen within it. If you wish, you can imagine a universe being drawn randomly from an infinite hat, containing all the natural numbers, where the universe is interpreted by means of a Universal Turing Machine. The fewer bits are necessary to specify a given dynamics, the more likely it is that the universe drawn from the hat will be isomorphic to said dynamics.

In this case, the existence of myriad stars and galaxies can be explained by the fact that it was a very simple disturbance to a highly compressible pattern that caused the Big Bang, making it far more likely to have been drawn from the universe hat than a universe which specified, in intimate detail, the exact configuration of a single solar system as its initial conditions. Similarly, the existence of a huge number of layers of abstractions of physical dynamics (e.g. quantum physics, chemistry, biology, anatomy, Newtonian physics, psychology), and the resulting applicability of reductionism to science, can be explained in this framework as a shortcut to specifying the upper layers - those governing conscious observers - directly. Weirdness about the curvature of spacetime can thus be chalked up as compression artifacts - just cosmological moire patterns. Essentially, this promotes Ockham’s razor from an instrumental rule of thumb to a fundamental metaphysical principle: to be likely to exist, a given system must have a simple description.

Note that this explanation says nothing about the weirdness of wave-function collapse, and its apparent ties to conscious observers. I consider these ties to be truisms, and illusions at best, due to the many-worlds theory. I will continue to elaborate on this aspect of my philosophy in my next post, The Arrow of Time.

Sense vs. Denotation, Interpreted vs. Compiled, and other false dichotomies

Mon, 01 Mar 2010 09:29:00 -0500

This post is about a deep, yet subtle, philosophical point. It’s being written at 8am by an author who hasn’t slept the previous night, and who admits that his idea is highly underdeveloped, but certainly merits more investigation. In short, it has all the marks of a meaningless crackpot theory that is hardly suitable for public consumption, and threatens the credibility of its author.

But, here I go writing it anyway, for this blog provides at least the illusion of an audience (hi!), and that will motivate me to organize my thoughts, which I believe might very well become my doctoral thesis. Please excuse the imperfect organization of thoughts here - I hardly expect this to be my best essay…

I’ll begin with a simple example, from Frege, to present the tip of the iceberg. Suppose we have an equation a=a. That doesn’t mean very much - without even knowing what a is, we can verify its truth. Now suppose we had an equation a=b. Intuitively, that must say something meaningful about a and b, which may or may not be true, depending on what they are. Yet if a=b, then the equation a=b should be equivalent to a=a - but we already determined that equation is significantly less meaningful. Frege resolves this as follows: “What is intended to be said by a=b seems to be that the signs or names a and b designate the same thing, so that those signs themselves would be under discussion; a relation between them would be asserted. But this relation would hold between the names or signs only in so far as they named or designated something.” In short, there is an important distinction between the name a (called a sense) and the object to which a might refer in a given context (called a denotation).

Here’s a much more concrete example (to me, at least) of a very similar distinction: programming languages can offer a call by name or a call by value feature. If a function is called by name with some argument foo, then the name foo is passed to the function, and it can use this name to locate a certain object in memory, which it can then process in some way. If, instead, the function is called by value with argument foo, the name foo is immediately interpreted, in the context of the calling function, and the resulting object copied to a new location in memory, which is directly passed to the called function.

A slightly less obvious connection to programming language theory can be made as follows. Some programming languages are compiled; others are interpreted. A program written in a compiled language must first be passed to a special program called a compiler, which parses the notation of the programming language into an abstract syntax tree, applies some transformations on it, and finally returns a natively executable machine code object (e.g., an .exe file) which has the behavior specified by the original program (known as the source code). On the other hand, a program written in an interpreted language is parsed into notation and executed at the same time, with a special program called an interpreter directly performing the specified behaviors as soon as it has extracted the relevant syntax. (In many interpreted languages, an error in syntax will go completely unnoticed by the interpreter until such time as the program is asked to perform the function in which the error is contained.) In this case, an interpreted-language program would correspond to the “sense” form, while the compiler would focus on the “denotation” of its compiled-language program.

[Aside: There is a somewhat newer model, followed by Java and the .NET languages, of compiling to an intermediate format, usually called bytecode, which is later interpreted by an interpreter (when the program is run). This way, syntax errors can be caught before the program is shipped, but it also does not need to be recompiled for every platform it needs to be used on (as purely compiled code usually does).]

In linguistics, the words syntax and semantics are often taken to refer to sense and denotation, respectively.

In mathematical logic, rewrite rules and algebraic equations correspond to sense and denotation. Rewrite rules must have a finite dynamics leading to some normal form, such that two expressions are equal iff the repeated application of the rewrite rules on each of them yields identical expressions in the normal form (we apply some syntactic processing to the senses of the expressions, and see if equal senses are derived). On the other hand, algebraic equations work both ways, and by purely random application of algebraic equations to two expressions denoting the same integer, one is unlikely to derive the same single number; yet the algebraic equations have the significant advantage of expressibility and mathematical clarity, since they do not rely on a particular notational standard.

It is now my goal to establish a coherent, cross-disciplinary middle ground between sense and denotation. In a couple rather narrower cases, some way forward is clear.

For instance, in compiled vs. interpreted programming languages, there is a natural sense of a partially compiled program, in which any computations that are well-specified to perform without knowledge of the program’s input should be pre-computed at compile-time, and likewise, any optimizations that can be applied given knowledge of the program’s input and target platform should be applied at run-time, thus largely eliminating the distinction between the two phases. This is not fully satisfactory, as there is still a clear distinction between “compiling-like” processes and “interpeting-like” processes; but I suspect it will be possible to blur this distinction significantly in implementation.
In a fascinating intersection between philosophy of mind and ontology, Daniel Dennett puts forward a position in his essay Real Patterns that is nicely between “materialism” and “realism” with respect to abstract objects, by making reference to information theory, and Kolmogorov complexity in particular. He claims that the degree to which an abstract object is real is the extent to which its description is a more compact representation of the underlying configuration. This nicely puts to rest, for instance, the classic philosophical question of “whether that table exists.”

That’s about all I have to say right now. In summary, I see a lot of distinctions as being reflections in various ways of the underlying sense-denotation dichotomy:

Dynamic vs. static typing
Interpreted vs. compiled languages
Syntax vs. semantics
Rewriting vs. algebra
Brain vs. mind
Behaviorism vs. functionalism
Micro-states vs. macro-states
Copenhagen vs. many-worlds
Reactive vs. proactive

Furthermore, I don’t see these distinctions as fundamentally necessary. Finally, I believe that resolving all of them at a single stroke would be a truly significant achievement, and I am interested in applying myself to this problem.

If I am committing any apparent fallacies here, or overlooking an obvious resolution, please let me know. Thanks!

iPhone photos

Mon, 01 Mar 2010 07:43:04 -0500

One of the shortcomings of the iPhone 3G is its integrated camera. Quite simply, it’s low-quality.

There are now several apps available to further destroy the image quality - but in a way that’s somehow artistically valuable, and subsumes the merely annoying deficiencies of the original:

It’s pretty impressive to me that you can even do this kind of image manipulation on the phone itself, and I rather like the results as well. Makes me want to upgrade to the 3GS, which has an even better camera (and provides hardware support for programmable exposure, which means HDR).

Which of the three images above appeals to your aesthetic sense the most?

Who doesn’t love the planetarium robot? :)

Mon, 01 Mar 2010 06:56:50 -0500

Who doesn’t love the planetarium robot? :)

This base in Tucson is where the US Air Force keeps all of its...

Sun, 28 Feb 2010 19:50:07 -0500

This base in Tucson is where the US Air Force keeps all of its old planes.

endlessforms:

via www.telegraph.co.uk

Like, Python

Sun, 28 Feb 2010 19:45:54 -0500

#!usr/bin/python
uh from sys import exit

# Grab the user's name. 
ok so like name = raw_input("yo! what's your name?") right
  
# Make sure they entered something, then say hi.
if name.strip() is actually like "":
   toootally just exit()
else:
   um yeah
   print like "Hi %s, nice to meet you." % name

Somebody actually implemented this dialect of Python.

engenharia: (via ladyengineer)

Sat, 27 Feb 2010 18:25:12 -0500

engenharia:

(via ladyengineer)

Live in a Missile Base

Fri, 26 Feb 2010 18:29:24 -0500

Live in a Missile Base

"The ARM was conceived as a processor for a tethered desktop computer, where ultimate low power was..."

Fri, 26 Feb 2010 18:24:40 -0500

“The ARM was conceived as a processor for a tethered desktop computer, where ultimate low power was not a requirement. We wanted to keep it low cost, however, and at that time, keeping the chip low cost meant ensuring it would go in low-cost packaging, which meant plastic. In order to use plastic packaging, we had to keep the power dissipation below a watt—that was a hard limit. Anything above a watt would make the plastic packaging unsuitable, and the package would cost more than the chip itself. We didn’t have particularly good or dependable power-analysis tools in those days; they were all a bit approximate. We applied Victorian engineering margins, and in designing to ensure it came out under a watt, we missed, and it came out under a tenth of a watt—really low power.”

- Steve Furber, on designing the ARM (in 1983!)

Character Strengths

Thu, 25 Feb 2010 03:04:00 -0500

The VIA Survey of Character Strengths would probably rank as my favorite personality test I’ve ever taken. Here is my report:

#1: Humor and playfulness You like to laugh and tease. Bringing smiles to other people is important to you. You try to see the light side of all situations.

#2: Forgiveness and mercy You forgive those who have done you wrong. You always give people a second chance. Your guiding principle is mercy and not revenge.

#3: Curiosity and interest in the world You are curious about everything. You are always asking questions, and you find all subjects and topics fascinating. You like exploration and discovery.

#4: Creativity, ingenuity, and originality Thinking of new ways to do things is a crucial part of who you are. You are never content with doing something the conventional way if a better way is possible.

#5: Hope, optimism, and future-mindedness You expect the best in the future, and you work to achieve it. You believe that the future is something that you can control.

#6: Love of learning You love learning new things, whether in a class or on your own. You have always loved school, reading, and museums-anywhere and everywhere there is an opportunity to learn.

#7: Judgment, critical thinking, and open-mindedness Thinking things through and examining them from all sides are important aspects of who you are. You do not jump to conclusions, and you rely only on solid evidence to make your decisions. You are able to change your mind.

#8: Fairness, equity, and justice Treating all people fairly is one of your abiding principles. You do not let your personal feelings bias your decisions about other people. You give everyone a chance.

#9: Social intelligence You are aware of the motives and feelings of other people. You know what to do to fit in to different social situations, and you know what to do to put others at ease.

#10: Appreciation of beauty and excellence You notice and appreciate beauty, excellence, and/or skilled performance in all domains of life, from nature to art to mathematics to science to everyday experience.