Archive for February, 2012

No Offense

Wednesday, February 29th, 2012

intended, but this post by Daniel Finke seems to me to be so wrong on so many counts that it deserves demands a rebuttal. (more…)

Abortion Discussion at Briggs’ Place

Wednesday, February 29th, 2012

This post (from a source I find sometimes interesting but often wrong) appears to take the simplistic (but common) position that the state of personhood which defines murder is discrete

In addition to agreeing with commenter Alex Heyworth that “logical consistency is not a necessary condition for moral codes, nor even a common one”, I would also claim that logic, even when it does apply, does not require that the marker used to separate what is legal from what is illegal should correspond to anything other than agreement by the majority (or by whoever has the deciding power in a given culture).

With regard to the legal question, there may well be agreement on many cases. But in the continuum between what certainly should always be allowed and what certainly should always be forbidden there is a range of cases on which people may disagree. In the absence of any universal agreement on the moral issue, what the law does is attempt to strike a balance between competing moral positions. Often this means that it just draws one or more lines of convenience without actually claiming that they separate the moral from the immoral. So a legal distinction at twelve weeks of gestation, or twenty, or whenever, does not need to imply that any particular state of the fetus changes at any of those times.

Even for the purpose of an individual moral decision, there may well be competing values at stake and I have never seen a good argument for the existence of a common scale on which such competing values can be compared. We each decide on what seems right at the time. In many cases we have no qualms about the choice, and the vast majority agree. But there is no guarantee that all cases will be this simple, and we are often faced with situations where a choice we have made in good conscience may later be felt to be wrong (and maybe later right again). Sometimes we do fall into indecisive mental “churning”. But even if we do make a choice, that does not imply the existence of a truly “best” moral decision. What tips the balance towards our actual judgement at any given time may depend on past experience and current neuro-chemistry rather than any absolute prioritization of competing values. However, despite the fears and fear-mongering of some, this does not deny the possibility of *any* absolute moral principles. There are lots of cases where we do have essentially universal agreement on what is right, and even more where careful consideration leads always to the same answer even among those who might initially disagree with it. But I suspect that any project to find a *complete* set of absolute moral principles will fail.

With regard to the personhood of a fetus I doubt that anyone believes in a magical discrete change of status at any particular time. But many people see the progression from fertilized ovum to conscious infant as a gradual process where the attitude towards killing should range from negligible concern at the start to absolutely abhorrence at the end. And although I don’t *require* logic in morality, I see no lack of it in such a position.

A Bayesian Paradox ?

Wednesday, February 29th, 2012

William M. Briggs post The Jeffreys-Lindley Paradox Isn’t

refers to this article at Science2.0 by Tommaso Dorigo

Ina  sense both seem to be saying the same thing but perhaps for different reasons. Dorigo concludes that there is no paradox because the two approaches are answering different questions – which is certainly the case from the numerical point of view but perhaps not the “moral” one. (ie the common “moral” question is “should we trust the detector?” and the two approaches do appear to give different answers.

My first stab at a response to Dorigo would be to suggest that a “proper” Bayesian approach (if there is one) should be constantly re-adjusting the priors in the light of observations to date. So by the time observation 1000000 rolls in here have already been many reasons (albeit not all independent of course) to abandon the 50% “delta function”. I haven’t given any rel thought to whether this would make a difference but my gut says it should.

As to Briggs, I need first to see how what he is saying differs essentially from Dorigo but, as usual, I find his talk of “the probability that T is true” to be off-putting at best. (Dorigo is less at fault for this because the specific context does give a sense of what that “probability” might mean whereas in Briggs discussion T is treated so abstractly as to give it no substance).

On Life Eternal

Wednesday, February 29th, 2012

Albert Einstein: “I cannot conceive of a god who rewards and punishes his creatures or has a will of the kind that we experience in ourselves. Neither can I—nor would I want to—conceive of an individual that survives his physical death. Let feeble souls, from fear for absurd egotism, cherish such thoughts. I am satisfied with the mystery of the eternity of life and a glimpse of the marvelous structure of the existing world, together with the devoting striving to comprehend a portion, be it ever so tiny, of the Reason that manifests itself in nature.”

Carl Sagan:”I would love to believe that when I die I will live again, that some thinking, feeling, remembering part of me will continue. But as much as I want to believe that, and despite the ancient and worldwide cultural traditions that assert and afterlife, I know of nothing to suggest that it is more than wishful thinking.
….
The world is so exquisite, with so much love and moral depth, that there is no reason to deceive ourselves with pretty stories for which there’s little good evidence. Far better, it seems to me, in our vulnerability, is to look death in the eye and to be grateful every day for the brief but magnificent opportunity that life provides.”

The Secret Life of Bees

Tuesday, February 28th, 2012

This article in  Smithsonian Magazine is not about the novel but is a nice clear exposition of a simple experiment designed to expose the process by which a swarm “decides” on where to locate its next hive.

Human democracy is a wonderful thing but it will never match the efficiency of bees. The bees (and neurons) are very closely related and so all have the same internal algorithm for relating strength and persistence of expression to the value of the proposition being expressed – and also, since none of the workers are fertile, there is no possible competitive advantage to having ones own “idea” chosen. But perhaps there is a useful lesson for us. If we want to minimize head-butting then we should strive for a highly egalitarian society with minimal fertility for decision makers.

Upper Class People More Likely to Cheat

Tuesday, February 28th, 2012

Despite the self serving concept of  “noblesse oblige”,  this report (which came to me via 3QuarksDaily) shouldn’t really be too surprising.

The title phrase “more likely to” doesn’t really suggest causation in either direction, but I suspect that it does actually work in both.

3QD commenter Jason Bosch points out that cheating (being the “defector” in a pool of cooperators) can be a source of wealth, and Elatia Harris aptly quotes Balzac: “The secret of great wealth with no obvious source is some forgotten crime, forgotten because it was done neatly.” But this last bit cuts both ways as it leaves the poor unsuccessful cheaters at the bottom of the heap – and unless we know how hard it is to cheat successfully we don’t know whether cheating per se is a net increaser or decreaser of status.

Successful cheaters are the ones who prosper without getting caught, and by doing so they get positive reinforcement for their cheating behaviour.

Another factor which might lead to the reverse causation (the one perhaps more likely to be inferred from the title) is the fact that those who are unjustly rich (whether by their own “earnings” or inheritance) are no less likely than anyone else to seek a story which justifies their wealth, and one effective such story is provided by a sense of entitlement (to whatever privileges happen to be available – including anything from children’s candy to handicapped parking spots).

“Race Finished” declares American Scientist

Monday, February 27th, 2012

This article at American Scientist was evidently not written in response to my Mythical Myth #3.

Indeed, it exemplifies the unfortunate tendency of well-intentioned people whom I would like to agree with to sabotage their own position by overstating the case and reacting to anything we don’t like by denying that it exists.

Anyone who looks can see that of course races exist. And to suggest that anything is unworthy of scientific interest is itself unscientific and foolishly unimaginative. For one thing the fact that we are so strongly aware of variations in a tiny fraction[1] of the genome is certainly a question of scientific interest (and one which may well have important practical and moral consequences if we can figure out how to minimize and control our reactions to those perceptions).

[1]Speaking of “tiny fraction” one of the most irritating things about those who quote numbers in polemics is the stupidity of giving a number like the percent of the genome which varies between races without any reference for comparison of what it is supposed to be “small” compared to (eg the percent variation which distinguishes us from chimpanzees for example)

Not so Selfish

Saturday, February 25th, 2012

3quarksdaily  excerpts from Peter Richerson’s  review in Nature of Samuel Bowles and Herbert Gintis’s A Cooperative Species: Human Reciprocity and its Evolution. They also link to a more critical view put forward by Michael Price in Evolutionary Psychology.

Animal Understanding of Animal Understanding

Tuesday, February 21st, 2012

Colin Allen (in American Scientist) reviews a book by Robert Lurz which takes what I am inclined to call a typical philosopher’s miss-take on the issue.

Apparently Lurz notes that an animal’s responses to another animal’s looking at food through a chink in the fence could, in principle, be just an instinctive response to the looking behaviour rather than being based on having some mental model of the mental state of the competitor.  He calls this the “logical problem” and claims that economy of thought favours the version with no mental modelling. But what I see there is an illogical appeal to false economy.

The possibility of alternative explanations is not of itself a problem. Every set of results admits a variety of “logically” possible explanations, and it is only by something like the principle of economy that we can make a choice. But in making this choice, economy of thought, like entropy, has to be considered globally rather than just locally.

Lurz’s “logical problem” applies also to my attribution of thought to fellow humans. Logically they could all be just mindless robots, but having learned to recognize myself (which elephants and chimps among others can also do) and seeing that other people do in fact look like me, it would be reasonable (and economical) to assume that when their behaviour matches mine it does so for similar internal reasons. Without access to my own thoughts and my own apparent similarity to my peers, their consciousnesses might seem like an unnecessary extra assumption, but in the extended observational context which includes myself, their minds become necessary in order to avoid the unnecessary distinction between minded people and the mindless others. Since my own experienced existence does render the mind-concept necessary it would be wasteful not to use it also to help explain the behaviour of others – even though, in my absence it may not have been necessary and so might have properly been ruled out.

More importantly, a theory of mind enhances my ability to predict the behaviour of my peers in a wider variety of circumstances than merely reacting to certain sepecific behaviours would. What evolution favours in me it also favours in my chimpish cousin – and has been doing for thousands of generations.  So again economy of thought suggests that if it looks like a chimp thinking of a thinking chimp and acts like a chimp thinking of a thinking chimp then it may well be a chimp thinking of a thinking chimp even if it can’t quite talk like a chimp thinking of a thinking chimp.

If a chimp could think of a chimp-thinking chimp with his eye on a chink what might he think that the chimp-thinking chimp with his eye on the chink would think?

 

Silly Questions?

Friday, February 17th, 2012

Statistical pundit William M. Briggs has written a piece for ‘Significance’ on Why Do Statisticians Answer Silly Questions That No One Ever Asks?.

Briggs is right to object to instances where statisticians (or more often users of statistics) respond to silly questions with the answers to different (and often equally silly) ones without making it clear enough that they are not answering the original question. But he is wrong in his presumption that the questions asked usually make sense.

In fact it is common to talk of probability in quantitative terms in situations where it is by no means clear what a specific numerical probability would mean.  Such talk is what gives rise to many well known “paradoxes” which can only be resolved by clarifying the interpretation.

But although Briggs alludes to recent advances in Bayesian analysis, he doesn’t seem to understand them well enough himself  – at least not well enough to answer a simple question about what he means when he says  “a civilian needs little or no maths to understand what ‘the probability that A is better than B is 80%’ means”. 

Briggs response to the question of what that understanding might be is just “It means the evidence is such that the probability ‘A is better than B’ is 80%. Which is greater than 0% but less than 100%. Nothing more.

When challenged that this is like claiming to explain what “the hoy is gerflumptive” means by saying that it means “the evidence is such that the hoy is gerflumptive”, he responds with “I wasn’t being glib. Probability (see above) is a measure of truth, or closeness to truth. 80% is closer than 70% and less close than 90% to being true. What you do with this number is different than what the number is.

Well, I’m sorry, but giving “closeness to truth” as a definition of probability *is* glib.

(It’s also more than 75% wrong in that I can think of at least three measures of closeness to truth that are more common than anything to do with probability.)

He asks for examples and I say:

For example, in common language (as per my claim):

1. an approximate answer is often referred to as close to the truth

2. a false statement is sometimes referred to as close to the truth if its error arises from a fairly common misuse of terminology

3. a detective may be said to be getting close to the truth if he has a good idea of where to look for the deciding piece of evidence

etc.

Briggs responds to these with:

But two of these examples are non-probabilistic.

1. Given our background knowledge, an approximate answer is likely true
3. Ditto

2. You’ll have to clarify this. A falsity is not close to a truth; a mistake is still a mistake.

Cooper:

They were intended to be non-probabilistic as I was giving them as examples of why “closeness to truth” is not a good definition of probability.
1. The statement that the circumference of a circle is six times its radius has zero probability of being true but it is close to the truth.
3. Knowledge of the fact that the murdered duke wrote a deathbed note which will tell me whether it was Colonel Mustard or Professor Plum who poisoned him brings me closer to the truth without increasing the probability of either hypothesis.
2. Your attempt to define probability as “closeness to the truth” may be close to the truth but it has zero probability of actually providing a useful definition.

Briggs:

Alan,

I assume you meant your “2″ as a joke, but it has backfired on you. In a useful way, however. Let’s see.

1. A = “The circumference of a circle is six times is radius.” Now, there is no such thing as

    Pr(A).

But we can calculate:

    Pr(A | E) = 0

where E = “My knowledge of geometry as might be found in any high school or higher text”. Notice that this is completely different than B = “A is a good approximation”. We still cannot calculate

    Pr(B).

But we can calculate:

    Pr(B | E & F) = 1

where we have the same E plus information F = “A good approximation is being within plus or minus 20% of the radius” or some other F (different F might change the probability, of course).

3. A = “Duke says M or P killed him”. If B = “M killed the Duke” then

    Pr(B | A) = 1/2

and similarly for C = “P killed the Duke.” The probability

    Pr(Duke was murdered | evidence of dead body & foul play) = 1

which is the same as

    Pr(Duke was murdered by somebody | evidence of dead body & foul play) = 1.

But we cannot compute

    Pr(Duke was murdered by M | evidence of dead body & foul play) = unknown,

unless we condition on something more, namely a list of suspects.

2. I could write this out, but you’ll get the idea. The probability that I have provided you the true definition, given all this (and other information on the blog) is 1.

Cooper:

All I can say is that I think you must have missed my point – which was that there are common language senses of “closeness to truth” which have nothing to do with probability, and so that “closeness to truth” is not a good definition of probability.

This all started when I asked you what you would say ‘the probability that A is better than B is 80%’ means, and so far I haven’t seen anything not glib in response.

Briggs:

Alan,

I haven’t; you have failed to make yours. In order to disprove my thesis, you need to show an example that can’t be written in the forms (for example) that I’ve given.

Cooper:

Thanks for trying, but I don’t understand what you are saying. If you have given an intelligible answer to my question about the meaning of probability then I guess I’ll just have to accept that the subject is beyond me.

Seriously, am I nuts or is this guy cuckoo?

Who’s Doing Bad Statistics?

Thursday, February 16th, 2012

Phil Plait, at Discover Magazine, objected to an article in the Wall Street Journal where a number of climate change skeptics claimed, among other things, that the last decade has seen no global warming. Plait asserted that this amounts to “blatantly misinterpreting long term trends, instead wearing blinders and only looking at year-to-year variations in temperature” and reproduced a shot from an animation in which the folks at skepticalscience.com demonstrate how there can be many periods in an upward trending time series over which the trend is not apparent.

William M. Briggs then accused Plait of doing “Bad Statistics” and in particular of ignoring “how the starting point made a big difference in the slope of the line, and how not accounting for uncertainty in the starting date translates into over-certainty in the results“. Briggs also questioned the provenance of the data in the graph and objected to the lack of error bars on the data points, but I am in no position to comment on those aspects except to note that the data apparently come from the Berkeley Earth Surface Temperature  project lead by former skeptic Richard Muller (see this WSJ article by Muller)who was critical of the processes used in previous data compilations but now believes that the month-by-month global average land temperature anomalies (differences from some kind of long term multi-year average for the given month – presumably designed to eliminate the effect of seasonal variation throughout each year) that they have put together do have value as measurements with known margins of error (which appear to be small compared to the month-to-month variations)

What I want to focus on is just Briggs apparent claim that the data do justify an assertion that the increase (in whatever it may be that they represent) has stopped.

This is the issue addressed in the animation and blog post from which Plait got his version of the Berkeley data and what is remarkable is that Briggs own post about cherry picking intervals from a time series contains the germ of why his claim is false.

The fact is that a time series involving a substantial amount of random variation around a trend may often (and, if the scale of the random fluctuations exceeds  the trend increase for one step, will always) include intervals where the trend appears to be reversed and the shorter the interval the more extreme the variation and reversal of apparent trend.

What is most remarkable though is the fact that Briggs (who does apparently have an academic background in statistics) has followed up his attack on Plait with a series of five posts purporting to give an explanation of Time Series Analysis which is supposed to be in support of the claim but so far as I can tell is either vacuous or nonsense.

And further that having claimed in an article that “a civilian needs little or no maths to understand what ‘the probability that A is better than B is 80%’ means” he was either unable or unwilling to say when asked (in a comment to his blog post advertising it) what he meant by that other than the glib and vacuous response “It means the evidence is such that the probability ‘A is better than B’ is 80%.”

I have not had quite such a sense of disconnect with a professional in the mathematical sciences before so I would like to check whether or not I am missing something

 

Social and Biological Construction(s) of Race

Monday, February 13th, 2012

This article by Razib Khan at Discover Magazine makes an important distinction which relates to my earlier post on the same topic (Mythical Myth #3). The fact that the strength of a concept can be widely misunderstood does not mean that it has no basis in fact, and to deny that it exists at all (when it so transparently does) can actually discredit and undermine efforts to prevent its abuse.

 

Contraceptive Coverage in US Health Care Plans

Friday, February 10th, 2012

The fact that, in the USA, having decent basic health insurance for all is dependent on some funny scheme involving employers is something that most of the “civilized” world finds hard to understand. But given that it is so dependent, thinking about the cost impact of paying for contraception as opposed to the alternative raises an interesting point about whose “freedom” is at stake when the catholic bishops insist on being able to exclude it for their employees.

Health insurance companies which are free to charge on a cost-plus basis have no incentive to require a cost-reducing preventive medicine if they are free to charge whatever the costs are without it. But If I was selling dependent coverage at a fixed rate independent of family size (as many group plans do), then I would probably be prepared to add birth control for free after negotiating the rate without it – unless of course the employer told me not to. So what may well be the case here is that the church was seeking to pay a premium for the right to *exclude* contraception from a plan which could have been cheaper with it.

If so, then the church has been making all this fuss because they want the freedom to pay extra themselves in order to deny their employees the freedom to get whatever birth control they need via the most economical route. If people can understand this (and if the media don’t suppress it) then it will be interesting to see where the mud finally sticks!

Will it “Take”?

Wednesday, February 8th, 2012

These messages are not new but maybe there’s  now at least a chance that they’ll rise in volume sufficiently to overhwelm the mainstream censors:

3quarksdaily links to Why economic inequality leads to collapse

and David Brin has some good words about the distinction between investment and rent seeking.

Time Series

Sunday, February 5th, 2012

William M. Briggs, a climate change skeptic who has been in a recent running battle with the other side ever since getting a podium at the Wall Street Journal is having a go at clarifying his position on Time Series.

In Let’s Try This Time Series Thing Again: Part I, Briggs starts with the idea of such a series as representing something that is “measured without error” and adds the claim that “Something causes every observation to take the values it does”. Both of these reduce my expectation that he has anything useful to contribute so maybe I should look up a serious reference on the topic and see if he’s really as far off base as I think he is.

ACTA

Friday, February 3rd, 2012

This confession came to my attention via Michael Geist.

Coincidentally this came at the same time via 3QuarksDaily, and I was also pleased to see that Neil Young has joined those who see the excessive criminalization of media sharing (and especially of  private copying) as ill advised.

Personally I am not a big user of commercial media, but the arrogant presumption of assholes stealing my money to pay for copying I will never do, and threatening to lock media that I do buy into playability only on proprietary platforms, has put me firmly in the pro-pirate camp. And I expect to stay there until the media world either rots away or comes to its senses and adopts a more reasonable and respectful attitude.

Mythical Myths #17: Humans radiate proportionately more than the Sun

Thursday, February 2nd, 2012

Sometimes a statement which is perfectly true is called a myth on the basis of a misstatement. A case in point is “Bad astronomer” Phil Plait’s treatment of the statement in the above title in the post at  Q&BA: Pound for pound, are humans hotter than the Sun? | Bad Astronomy | Discover Magazine.

The correct statement of the mythical “myth” is that pound-for-pound (or ml-for-ml) the human body radiates more energy per second than the sun. Of course it’s not “hotter” nor does it *have* “more energy”, but it *loses* energy relatively more quickly because it has a relatively much larger surface area compared to its volume. This is just a consequence of the relative inefficiency of large spheres as radiators.  The reason for this is because any old cc in the middle of the sun may be as hot as hell but they all absorb almost as much radiation from their neighbours as they emit themselves, and it is only those near the surface which contribute photons which actually escape. So the idea of pulling them out to compare with us defeats the whole point of the exercise. It’s all part of the same theme which explains why elephants have big ears and why mice each day have to eat a much greater proportion of their body weight than we do. If I was as fat as the sun I’d be pretty hot in the middle too and that’s precisely because I would then be getting rid of heat proportionately less rapidly than I was generating it.