Follow Slashdot blog updates by subscribing to our blog RSS feed

 



Forgot your password?
typodupeerror

Comment Re: ...if impurity levels grow with time. (Score 5, Insightful) 174

No wonder people doubt climate change when scientists say things like this..

I'm just guessing here based on nothing but a few decades of involvement in the scientific community, but I'd say it's pretty likely that a) the scientists in question have thought of your objection already and b) they have quantified the relative contributions from increased grain size vs increased dark pollutants.

What would be incredibly stupid is assuming that people who study this stuff professionally can be out-thought by a random Internet commenter who has just encountered the question for the first time.

But just in case, let me ask you: what is the quantitative relationship between grain size and reflectivity of snow? Please respond with a graph or formula. You must have access to this information to judge the relative importance of grain size vs pollutant cover, and it would be a positive contribution to this discussion to share it.

Comment Re:What an ego mania. (Score 1) 161

"Todayâ(TM)s strict evolutionists are unhappy about Darwinâ(TM)s views, for even today he would be unable to provide a satisfactory explanation"

Pretty much everything he says about evolution is wrong, and this is utterly wrong, particularly with regard to the "transition fossils" question it seems to be referring to. There are plenty of transition fossils. It's simply not an issue any more.

Darwinian theory predicted that there would be transition fossils. In Darwin's day transition fossils had not been found. Today they have, in abundance. To claim otherwise is to divorce yourself from simple, ordinary truth.

Furthermore, the invoke God as the "simplest explanation" for the diversity of life is to claim that somehow God, who is by definition incomprehensible according to Scripture, is somehow "simpler" than a process that necessarily follows from the chemistry of carbon compounds and the laws of probability as we currently understand them: http://www.amazon.com/Darwins-...

Comment Re:Limits of incremental change or other constrain (Score 1) 190

Is this just because "radically alter facial morphology" isn't one of those things you evolve even remotely quickly, or without changing a hell of a lot of genes, some of which have other functions, or do we suspect that there are competing constraints working against, or at least limiting, the degree that masculinized facial features are allowed to make you look like some sort of bio-tank?

Because of the degree of randomness in evolution by variation and natural selection, there are very few limits imposed by the incremental nature of the process. Random steps can take a locally deleterious feature a long way "up hill" in terms of fitness before it gets lost entirely from the population, and that process may well carry it over into a new local minimum that was deeper than the one it drifted out of.

That said, there are quite likely strong constraints on facial morphology that put limits on armouring. The human face is extremely important as a communications device, and remember: selection is driven by the differential probability of getting laid and creating successful offspring (where "successful" means... "getting laid and...")

So for example, blood flow in the face is a very important communications tool. There is reason to believe that the whole point of human's red/green colour acuity is so that we are maximally sensitive to variations in blood flow in each others' skins, particularly in the face. So variations that substantially reduced that already-subtle signalling channel would plausibly reduce the chance of those individuals getting laid.

Likewise, facial flexibility and mobility are important aspects of communication between humans (and likely proto-humans), and so on. Because we are by nature social primates, the effective communication goes beyond simple mate competition, too: the ability to form viable troops, work together cooperatively, etc, all will affect the individual's reproductive fitness, particularly when kin-selection is factored in (my genes will go on if my siblings and cousins are successful at mating, even if I am not, so my contributions to their success matters in the evolutionary process.) [Of course, there are also completely kooky speculative ideas about group selection, which are fun to play with: http://www.amazon.com/Darwins-...

Comment Re:Falling funding: Why fusion stays 30 years away (Score 1) 135

You need to spend your energy on something that will actually happen, even if it's not as good in theory.

Prediction is hard, especially with regard to the future.

Anyone posting on /. ought to be well aware of the long, long history of technical prognostications of exactly the kind you are posting here that turned out to be utterly, absolutely wrong.

I won't fault any of your numbers, but failure to acknowledge the role of serendipity in the history of science and technology is just a statement of your own ignorance, not a convincing argument. This is why public funding for things like fusion power is important: because the most corporate funding is based on a greedy algorithm. It simply heads toward the deepest local minimum. The history of science and technology--to say nothing of optimization theory--tells us that such an approach will miss a lot of interesting and important stuff.

And yes, this is a recipe for throwing away a lot of public money on things that a) won't work and b) can reasonably be expected to not work. Someone has to take those risks, though, if we are ever to get the benefits of the odd thing that does work, regardless of "proofs" to the contrary. The arguments against the viability of fusion, while significant, are not at the level of strength that suggests we shut the whole enterprise down quite yet.

Comment Re:Article doesn't go into details about quality (Score 2) 135

The waste would be just as hard to deal with as current nuclear waste is, although it would be produced in much smaller quantities.

Not quite. Because fusion reactors will contain mostly light elements, the waste produced will be almost all relatively short-lived (decades or years or less, not centuries). This is a huge benefit over fission, which necessarily creates a great deal of long-lived waste simply by virtue of neutron irradiation of heavy elements.

I do agree that fission (today) and fusion (in the future) are far better alternatives to base-load coal than anything else going, and get frustrated no end with self-proclaimed "environmentalists" who will do anything--absolutely anything--to stave off climate change except admit they were wrong about the risk-reward proposition on nuclear back in the '70's.

Comment Re:I'm ignorant (Score 2) 105

Given enough data, almost all hypotheses are disproven. The ones which remain and have not yet been disproven by evidence become theories.

Science is the discipline of publicly testing ideas by systematic observation, controlled experiment, and Bayesian inference. The last one is important, because Bayesian inference never "proves" or "disproves" anything in the Cartesian (or Poperian) sense of those terms. It instead increases or decreases the plausibility of propositions.

At best, "proof" and "disproof" are convenience terms that mean "overwhelmingly plausible with no alternative that has remotely similar plausibility" and "hugely implausible regardless of alternatives."

The asymmetry that Popper pointed out still exists on the Bayesian view: an extremely plausible idea may turn out to be in competition with unknown alternative ideas (think Newtonian gravity vs General Relativity) that are incrementally more plausible. Newtonian gravity (in its modified form) is still fairly plausible (although I don't think anyone really accepts it is better than GR), unlike, say, phlogiston theory, which is utterly implausible.

This is important because it means we don't have to accept the "most plausible" idea as "true"--the Bayesian standard of plausibility is absolute, not relative. It just never reaches a value of 1.0, only 1 - epsilon (or conversely epsilon for a maximally implausible idea.)

Bayesianism is compatible with "I don't know" as an answer when all current ideas have very low plausibility, and with "This is good enough for going on with" when one idea alone has high absolute plausibility, and "Could be this or that" when two or more ideas have similarly high plausibilities.

Comment Re:Skeptics (Score 3, Interesting) 105

The only thing we know for certain is all the extraterrestrial material we have analyzed so far from the rest of the solar system has had very different ratios of the isotopes, and so this evidence requires a whole new theory about the homogeneousness of the solar system to be true.

Not exactly. One thing missing from the popular discussions of this question is why we believe that isotope ratios necessarily vary across all larger bodies in the solar system.

It is true that measurements on meteorites show different ratios from what we see on Earth, but no particular conclusion can be drawn from that. It certainly does not follow from "None of the people I measure are the same height" that "No two people anywhere are the same height", so it would be bizarre in the extreme to go from a sample of fairly odd, mostly non-planetary, space rocks to a sweeping generalization about what is necessarily the case across the whole solar system. There may be some theoretical reason for believing this to be the case, but I've never seen it mentioned in any of the articles on this subject.

Furthermore, Theia has a very, very special property: its orbit intersected that of Earth's almost instantly after its formation. This is not the case with meteors, which have been wandering the solar system for more than four billion years, and therefore likely formed in very distant regions. Theia almost by necessity formed in a similar orbit to that of Earth. We know this, because only a body that formed in a similar orbit would likely find itself in a collision with Earth almost immediately after formation.

None of this "proves" or "disproves" anything, mind, because we're talking about knowledge here, not faith. Knowledge is by its nature uncertain, and the quest for certainty is simply an error pursued by pre-scientific peoples (philosophers), no different from the alchemical pursuit of transmutation of base metals into gold, or attempts to build perpetual motion machines, or attempts to trisect angles with nothing but straight-edge and compass.

Comment Re:Controllers for PC? (Score 1) 174

That is interesting given that my brother and my cousin - both big into gaming - use PC-style controls with their Xbox because they feel it gives them an edge over users of the Xbox controller

Which raises the burning question: why is anyone reporting user feelings rather than actual data to /.? It's the 21st century... surely by now everyone on here knows that how people feel and what is actually going on are almost completely decoupled.

Some people "feel" that wifi is interfering with their qi, even though the data show that no such effect occurs (that is, no one is able to tell if wifi signals are turned on based on such feelings.)

Ten years ago a surgeon I know worked on a study of post-operative pain in people with knee implants to see if different implants made a difference to patient outcome. While there were some objective measures (range of motion, etc) that showed a correlation with a suspect implant, simply asking patients about pain revealed only one thing: how much they liked their surgeon.

Psychology literature is full of things like this: it is an uncontroversial fact that what we feel is a lousy indicator of anything except our own internal state. Feelings are facts. They are just facts about us. While sometimes facts about us are important, they are a terrible gauge of anything else. Reporting feelings as if they were relevant to the actual edge a player has is exactly like saying, "My brother and my cousin--both big into gaming--use PC-style controls with their Xbox because the are both six feet tall, so they say this gives them an edge over users of the Xbox controller". "Being six feet tall" is a fact about them, just like "feeling it gives them an edge" is a fact about them. It is not a fact about the rest of the world (that is, their actual performance).

I'm being long-winded and pedantic about this (because hey, this is /.) but the parent was such a nice example of this extremely common failure mode in human thinking (confusing facts about ourselves with facts about the rest of reality) that it was too good an opportunity to pass up. That's how I feel about it, anyway...

Comment Re:Particles are more unique than thought (Score 2) 62

Two hydrogen atoms are completely unique to one another...

That statement is false. Quantum mechanics deals explicitly with "identical particles", which are particles that are literally indistinguishable from each other, but are not the same particle. This is an empirically demonstrable violation of the principle of "identity of indiscernibles", which states that if two things are indiscernible any means whatsoever, even in principle, they are the same thing. Even though we have known this principle to be false for almost a century, philosophers still take it seriously for some reason.

There is a relatively simple proof that atoms of the same kind are indiscernible. The heat capacity of solids is a measure of how much the temperature goes up as you add energy to a block of material. The temperature is just the average energy per vibrational mode of the crystal lattice. The number of vibrational modes is intimately linked to the number of distinguisable particles in the crystal. N distinguishable particles have a different number of modes than N indistinguishable particles, so crystals will have a different heat capacity depending on which situation actually obtains.

This can be seen by considering a pair of distinguishable coiins vs a pair of indistinguishable coins. If we have two coins that are distinguished by the labels A and B, we have four ways of arranging them by which face is showing (H for heads, T for tails): AH/BH, AT/BH, AH/BH, AT/BT. If they are not distinguishable we only have three states: H/H, H/T, T/T because there is no way to distinguish AT/BH from AH/BT when we remove the labels.

So by a simple macroscopic measurements like the heat capacity of crystalline solids we can prove positively and directly by experiment that atoms of the same kind are in fact indistinguishable, and that the principle of the identity of indiscernibles is false. It is not false "for quantum particles" but false, absolutely--it just happens that quantum particles are the only case we know of where different particles are genuinely indiscernible from each other. But there is no limited domain of application to this result, and philosopher's attempts to treat it as somehow restrictive to the quantum domain are simply misguided (it turns out that the identity of indiscernibles being false makes nonsense of a bunch of other things philosophers want badly to believe, not least of which is how utterly useless the human imagination is in deciding what is and is not true of the world.)

Comment Re:pffff.. (Score 1) 147

And that's the problem with a lot of scientists, they can only think in what already has been theorized and can't look beyond that..

Except, of course, you are commenting on an article that is very literally about scientists "looking beyond" what has been theorized.

Perhaps you mean instead that scientists are rarely given to baseless imaginings that violate current theory when they have no empirical basis for doing so. That is a good thing: people who attempt to understand the world by using their imaginings of how it might be or ought to be as their primary tool are called "philosophers", and they have failed to materially advance our understanding of the world significantly over thousands and thousands of years.

There is a reason for this: despite its many virtues, the human imagination is a terrible instrument of understanding. The world simply does not work in the ways we find it easy to imagine, and we find it hard to image the ways it does. We are incapable of imaging things the way they actually are (quantum spooky actions at a distance) and capable of imagining things that are impossible (perpetual motion machines, flying horses, etc.)

So it isn't a problem that scientists are reticent about using a tool that has proven to be lousy to understand the world. It is a problem that people who know nothing about science keep complaining about that.

Comment Re:pffff.. (Score 2) 147

Meanwhile, the mainstream media hears that and reports it either as "Scientists say this shouldn't happen. The universe is fucked up" or "Scientists say this shouldn't happen. Science is fucked up" depending on their political bent.

Also, don't forget the ever-popular, "Scientists are flip-floppers who can't make up their minds, while my ancient religion is always the same, century after century!"

The same strain runs through all of these: the implication that scientists should feel humiliated because what they thought to be highly plausible has turned out to be much less so. So long as people believe this--that being a good Bayesian and adjusting your beliefs in the face of new evidence is somehow shameful and "unmanly"--we will be stuck in this mire of evidence-free policy-making and anti-science gibberish on all sides.

Comment Re:Not Quite a Resounding Success (Score 1) 73

If you're so clever, show us your system which does this. Oh, wait, you don't have one, do you?

Actually, I do. It's called my arms.

I really wish people would stop using "brain controlled" for "brain plus millions of dollars of specialized machinery to replace your arms controlled". Saying something is "brain controlled" tells us nothing--it's like calling heavier-than-air flight "massive flight", or fixed-wing aircraft "aerofoil flight". The terminology does nothing to differentiate one thing from another.

While this may seem like a trivially pedantic cavil, it has been my experience that terminology that differentiates on the basis of non-essentials very often ends up misleading laypeople. There is already a robust mythology of disembodied brains as viable objects of philosophic consideration (really) this kind of sloppy language is at the very least not helping.

So can we please start calling these "arms free controllers" or similar, and acknowledge that there is always a brain involved? We're replacing the interface, not introducing a brain. It's like calling a touch-screen machine a "CPU controlled computer" because it lacks a keyboard.

Comment Re:Ai is inevitable (Score 1) 339

it is not. It's a fixed real thing that exists.

Which has nothing at all to do with computability.

We are not Turing machines. This is obvious. Turing machines don't have I/O. Turing machines don't have sensors or effectors. We do.

We can and do interact with the world in ways that Turing machines do not, and those interactions are a fundamental aspect of our intelligence.

This means that we can compute things that Turing machines can't. If we coupled a Turing machine to senors and effectors (that is, built a robot) it would have the potential to be as intelligent as we are, but it would no longer be a Turing machine and would be able to reach conclusions about non-computable problems, just as we can.

Turing computability is one very, very limited aspect of intelligence. Interaction with the world is at least as important.

Comment Re:What the f*$# is wrong with us? (Score 5, Insightful) 1198

But throwing one group under the bus to stand up for another still results in just as many people getting hit by the bus.

The thing that all these finger-wagging missives fail to take into account is that masculinity, like femininity, is a social construct. There are underlying biological differences between the male and female populations, but there are also broad distributions of individual characteristics, and the gender binary model attempts to impose a crisp, discontinuous division between "masculine" and "feminine".

In doing so, it does violence to anyone who fails to fit very well with the nominal masculine or feminine ideals of the society they happen to find themselves in.

The feminist movement has done a reasonably good job, more-or-less, in pointing out how these forces operate to shape women's lives.

We have done a lousy job of appreciating that the same kinds of forces shape men's lives as well, so we get these ridiculous claims that individual men are creatures of perfect agency, utterly unaffected by the social forces that are attempting to bludgeon them into good little emotionless soldiers (or whatever your society's favoured model of masculinity is at the moment). Telling profoundly damaged, struggling individuals to "stop whining" and so on is the opposite of what they need. They need to be told: "I feel you pain, but I hate your behaviour..."

The utter lack of compassion for men, and the complete lack of awareness of how the social construction of masculinity affects them, is one of the most depressing things about the current discourse on these issues.

None of this excuses individuals who behave badly, but if we want men to get better, we have to stop failing them as completely and systematically as we are now. We have to start valuing their lives, their experiences, their reality, rather than simply hitting them harder with various real and rhetorical hammers when they refuse to fit into the socially constructed masculine role that has been prepared for them.

Comment Re:Errors (Score 4, Insightful) 230

The slightly surprising part is that the misclassified images seem so close to those in the training set.

With emphasis on "slightly". This is a nice piece of work, particularly because it is constructive--it both demonstrates the phenomenon and gives us some idea of how to replicate it. But there is nothing very surprising about demonstrating "non-linear classifiers behave non-linearly."

Everyone who has worked with neural networks has been aware of this from the beginning, and in a way this result is almost a relief: it demonstrates for the first time a phenomenon that most of us were suspicious would be lurking in there somewhere.

The really interesting question is: how dense are the blind spots relative to the correct classification volume? And how big are they? If the blind spots are small and scattered then this will have little practical effect on computer vision (as opposed to image processing) because a simple continuity-of-classification criterion will smooth over them.

Slashdot Top Deals

"Lead us in a few words of silent prayer." -- Bill Peterson, former Houston Oiler football coach

Working...