setembro 25, 2012
The differences between speech and violence are not the differences between words and acts, or between good and evil.
Some speech promotes violence, like teaching xenophobia or religious intolerance. Some violence protects speech, like the lawful actions of the police in a free society. The line between speech and violence is too blurry, they overlap too much on each other. Why can't someone publicly deny historical or scientific facts? Why can't religious people verbally express their emotions against heresy? This is not about spreading false personal accusations (like defamation) or taking advantage of someone's name or work (like plagiarism or fraud). The argument is symmetric: there should be nothing wrong about denying or showing disrespect about beliefs or to argue how unfounded are certain system of ideas. For example, it is wrong for a society to apply violence or censorship to the ones exposing Homeopathy for what it is (a placebo) and it is also wrong for the same society to prohibit the expression of homeopathic ideas (which is not the same as allowing people to sell homeopathic products branded as medicine, which they are not, but that is a matter of fraud, not a matter of free-speech).
One role of the state is to protect its citizens. The state will always classify and restrict variants of violence and speech. In the category of 'violent speech' it is common to find notions like libel, slander, obscenity, hate speech, blasphemy, incitement. Each society adapts the broadness of this category, but we will not find a society that dismiss the idea entirely. And this is because speech can be violent and every feasible society always restricts violence one way or the other.
The focus should be in the discourse's subject. Is it about people, communities, specific individuals, or is it about ideas, opinions, beliefs? People have rights, ideas do not. No one owns an idea, no person 'is' one. Every criticism over an idea should never be interpreted as violence against its believers, even if they see it that way. There’s no right to not be offended. On the other hand, a verbal and personal attack can be interpreted as a violent act, just like a punch. Only the latter, not the former, should concern the judicial system. This is the difference between blasphemy and hate speech, between mocking ideas and defaming communities. Religions are systems of ideas and rituals. A religion has followers but it is not them. The same goes with Ideologies or Corporations. All systems of belief should and must be open to criticism. Every free society that gives them protective status walks a messy and dangerous path. People are, by definition, worthy of respect. Beliefs must strive to be.
setembro 24, 2012
What is a random variable? That’s easy. It’s a measurable function on a probability space. What’s a probability space? Easy too. It’s a measure space such that the measure of the entire space is 1.
Probability theory avoids defining randomness by working with abstractions like random variables. This is actually a very sensible approach and not mere legerdemain. Mathematicians can prove theorems about probability and leave the interpretation of the results to others.
As far as applications are concerned, it often doesn’t matter whether something is random in some metaphysical sense. The right question isn’t “is this system random?” but rather “is it useful to model this system as random?” Many systems that no one believes are random can still be profitably modeled as if they were random.
Probability models are just another class of mathematical models. Modeling deterministic systems using random variables should be no more shocking than, for example, modeling discrete things as continuous. For example, cars come in discrete units, and they certainly are not fluids. But sometimes it’s useful to model the flow of traffic as if it were a fluid. (And sometimes it’s not.)
Random phenomena are studied using computer simulations. And these simulations rely on random number generators, deterministic programs whose output is considered random for practical purposes. This bothers some people who would prefer a “true” source of randomness. Such concerns are usually misplaced. In most cases, replacing a random number generator with some physical source of randomness would not make a detectable difference. The output of the random number generator might even be higher quality since the measurement of the physical source could introduce a bias. John D. Cook
Por João Neto às 15:40
setembro 23, 2012
"The central dogma of statistics is that data should be viewed as realizations of random variables. This has been a very fruitful idea, but it has its limits. It’s a reification of the world. And like all reifications, it eventually becomes invisible to those who rely on it." John D. Cook
"Statisticians can get awfully uptight about numerical approximations. They’ll wring their hands over a numerical routine that’s only good to five or six significant figures but not even blush when they approximate some quantity by averaging a few hundred random samples. Or they’ll make a dozen gross simplifications in modeling and then squint over whether a p-value is 0.04 or 0.06. The problem is not accuracy but familiarity. We all like to draw a circle around our approximation of reality and distrust anything outside that circle. After a while we forget that our approximations are even approximations." John D. Cook
Por João Neto às 10:17
setembro 06, 2012
"A well-made language is no indifferent thing; not to go beyond physics, the unknown man who invented the word heat devoted many generations to error. Heat has been treated as a substance, simply because it was designated by a substantive, and it has been thought indestructible". The Foundations of Science, Henri Poincaré
Por João Neto às 10:09
setembro 03, 2012
"[...] in 1980, U.S. federal usury laws, which had previously limited interest to between 7 and 10 percent, were eliminated by act of Congress. Just as the United States had managed to largely get rid of the problem of political corruption by making the bribery of legislators effectively legal (it was redefned as "lobbying"), so the problem of loan-sharking was brushed aside by making real interest rates of 25 percent, so percent, or even in some cases (for instance for payday loans) 120 percent annually, once typical only of organized crime, perfectly legal-and therefore, enforce able no longer by just hired goons and the sort of people who place mutilated animals on their victims' doorsteps, but by judges, lawyers, bailiffs, and police." (pg.376) Debt, The First 5000 Years, by David Graeber (2011)
Por João Neto às 18:55