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Showing posts with label Andrew Gelman. Show all posts
Showing posts with label Andrew Gelman. Show all posts

Thursday, December 6, 2018

Bad science vs scientism

Here are a pair of papers (here,here) that discuss scientism. Scientism is hard to define exactly for it relies on being able to distinguish what is scientific from what is not and those that think that some piece of work is scientistic also generally think that demarcating science from non-science is a mug’s game. The longer paper is by Susan Haack. The shorter is a comment by Andrew Gelman who adds a codicil to her 6 distinguishing features. Here is Haack’s list:

1. Using the words “science,” “scientific,” “scientifically,” “scientist,” etc., honorifically, as generic terms of epistemic praise.
2. Adopting the manners, the trappings, the technical terminology, etc., of the sciences, irrespective of their real usefulness.
3. A preoccupation with demarcation, i.e., with drawing a sharp line between genuine science, the real thing, and “pseudo-scientific” imposters.
4. A corresponding preoccupation with identifying the “scientific method,” presumed to explain how the sciences have been so successful.
5. Looking to the sciences for answers to questions beyond their scope.
6. Denying or denigrating the legitimacy or the worth of other kinds of inquiry besides the scientific, or the value of human activities other than inquiry, such as poetry or art.

Gelman adds a distinction between active vs passive scientism. Here’s how he elaborates this distinction:

A familiar examples of passive scientism is “pizzagate”: the work, publication, and promotion, of the studies conducted by the Food and Brand Lab at Cornell University. Other examples include papers published in the Proceedings of the National Academy of Sciences on himmicanes, air rage, and ages ending in 9.
In all these cases, topics were being studied that clearly can be studied by science. So the “scientism” here is not coming into the decision to pursue this research. Rather, the scientism arises from blind trust in various processes associated with science, such as randomized treatment assignment, statistical significance, and peer review.
In this particular manifestation of scientism—claims that bounce around between scientific journals, textbooks, and general media outlets such as NPR and Ted talks—there is no preoccupation with identifying the scientific method or preoccupation with demarcation, but rather the near-opposite, an all-too-calm acceptance of wacky claims that happen to be in the proximity to various tokens of science.

I am not sure that what Gelman notes constitutes a natural kind with what Haack is worried about. Moreover, I think that the distinction is worth preserving if for no other reason that we need to allow for badscience, which is what Gelman is really pointing at. Bad science is science badly done and one can do things badly in a variety of ways, including in a way that rightly irks Gelman: “blind trust in various processes associated with science.”But this is still different from what Haack is trying to dissect which is more along the lines of a category mistake: the extension of scientific methods and modes of discussion into domains where they don’t really apply so as to join the slip stream of prestige that scientific inquiry enjoys.  The difference between scientism and bad science is sorta like the difference between bullshit and lies. Both are bad but they are not quite the same thing.

But once we are cataloguing, let me add one of my own pet peeves: the refusal to actually criticize what is being asserted. FoL has canvassed many “debates” wherein critics have attacked a position that nobody defended. Dan Everett on universals is a classic example of a “debate” based on a pun. But there are many others as well. A kissing cousin of this is the “refutations” of PoS arguments for one or another conclusion where the critic often has no idea what the PoS argument consists in. I would think that a useful rule of scientific method is to make sure that you read and understand that which you are objecting to. But the ubiquity of “critiques” and “refutations” that ignore this simple principle suggests that I would be wrong to think so.

I have been privy to a more recent version of this kind of criticism. For the last several years I have been arguing that Minimalism has been a tremendous success when evaluated in its own terms.  The papers and presentations that try to make this case lay out what I take the Minimalist project to be and how various proposals have succeeded in illuminating the questions it poses for itself. In particular, the project is to explain why we have the FL/UG we do and this project only makes sense given certain presuppositions and judgments (e.g. the project is decidedly mentalistic, it presupposes that many of the laws of grammar that GB style theories have discovered are roughly accurate, etc.). Most of my presentations spend a large amount of time spelling out these presuppostions and judgments and explaining how giventhese, Minimalism has offered plausible and defensible answers to the questions identified. I even make the point that ifone rejects these presuppositions or has made different empirical judgments regarding the presupposed facts that the Minimalist project as outlined will not appear particularly appealing. And I often add that there is no disputing taste (here I am being concessive, for I think that this is false) but that this is not relevant to the evaluation of the project’s achievements. And what does this get me? Mostly very little. Here is what I mean.

More often than not this does not satisfy everyone who reads the paper or attends the lecture. I cannot imagine why for as indicated I am always perfectly persuasive, gregarious, open-minded and mentally flexible. Still, I often fail. Why? Because so far as I can tell many just don’t like the very idea of the Minimalist project and think that working on such a project is illegitimate. Of course one cannot just assert “I just don’t like Minimalism!” and declare “Nor should anybody else!” because saying these sorts of things will make one sound like a crank. So, to avoid sounding like a petulant whack-job an MP hater will typically reach for generic criticisms (e.g. it’s not methodologically scientific, its ideologically driven, look at all the problems, etc.) that do not in any obvious way tie up to the premises defended or the arguments proffered. And this is, IMO, unkosher science. It’s fine not to like something. It’s fine to follow your gut. It’s fine to openly sneer at the taste of others (ok, that is notfine, but at least it can he done honestly). But it is not fine to pretend to offer criticism that seems based on reasons but is actually based on either ignorance, petulance, or mental indigestion. This is simple bad faith. And, sad to say, IMO, there is a lot of this in the sciences in general, and even in parts of contemporary linguistics. 

So what would I add to the Haack-Gelman discussion. I would add that there is a lot of junk science out there and much of it is driven by bad faith. This bad faith is illustrated by a refusal to address the actual arguments being made. And this is not a great thing.

Monday, August 27, 2018

Revolutions in science; a comment on Gelman

In what follows I am going to wander way beyond my level of expertise (perhaps even rudimentary competence). I am going to discuss statistics and its place in the contemporary “replication crisis” debates. So, reader be warned that you should take what I write with a very large grain of salt. 

Andrew Gelman has a long post (here, AG) where he ruminates about a comparatively small revolution in statistics that he has been a central part of (I know, it is a bit unseemly to toot your own horn, but heh, false modesty is nothing to be proud of either). It is small (or “far more trivial”) when compared to more substantial revolutions in Biology (Darwin) or Physics (Relativity and Quantum mechanics), but AG argues that the “Replication revolution” is an important step in enhancing our “understanding of how we learn about the world.” It may be right. But…

But, I am not sure that it has the narrative quite right. As AG portrays matters, the revolution need not have happened. The same ground could have been covered with “incremental corrections and adjustments.” Why weren’t they? The reactionaries forced a revolutionary change because of their reactions to reasonable criticisms by the likes of Meehl, Mayo, Ioannidis, Gelman, Simonsohn, Dreber, and “various other well-known skeptics.” Their reaction to these reasonable critiques was to charge the critics with bullying or insist that the indicated problems are all part of normal science and will eventually be removed by better training, higher standards etc. This, AG argues, was the wrong reaction and required a revolution, albeit a minor one relatively speaking, to overturn.

Now, I am very sympathetic to a large part of this position. I have long appreciated the work of the critics and have covered their work in FoL. I think that the critics have done a public service in pointing out that stats has served to confuse as often (maybe more often) than it has served to illuminate. And some have made the more important point (AG prominently among them) that this is not some mistake, but serves a need in the disciplines where it is most prominent (see here). What’s the need? Here is AG:[1]

Not understanding statistics is part of it, but another part is that people—applied researchers and also many professional statisticians—want statistics to do things it just can’t do. “Statistical significance” satisfies a real demand for certainty in the face of noise. It’s hard to teach people to accept uncertainty. I agree that we should try, but it’s tough, as so many of the incentives of publication and publicity go in the other direction.

And observe that the need is Janus faced. It faces inwards to relieve the anxiety of uncertainty and it faces outwards in relieving professional publish-or-perish anxiety. Much to AG’s credit he notices that these are different things, though they are mutually supporting. I suspect that the incentive structure is important, but secondary to the desire to “get results” and “find the truth” that animates most academics. Yes, lucre, fame, fortune, status are nice (well, very nice) but I agree that the main motivation for academics is the less tangible one, wanting to get results just for the sake of getting them. Being productive is a huge goal for any academic, and a big part of the lure of stats, IMO, is that it promises to get one there if one just works hard and keeps plugging away. 

So, what AG says about the curative nature of the mini-revolution rings true, but only in part. I think that the post fails to identify the three main causal spurs to stats overreach when combined with the desire to be a good productive scientist.

The first it mentions, but makes less off than perhaps others have. It is that stats are hard and interpreting them and applying them correctly takes a lot of subtlety. So much indeed that even experts often fail (see here). There is clearly something wrong with a tool that seems to insure large scale misuse. AG in fact notes this (here), but it does not play much of a role in the post cited above, though IMO it should have. What is it about stats techniques that make them so hard to get right? That I think is the real question. After all, as AG notes, it is not as if all domain find it hard to get things right. As he notes, psychometricians seem to get their stats right most of the time (as do those looking for the Higgs boson). So what is it about those domains where stats regularly fails to get things right that makes it the case that they so generally fail to get things right?  And this leads me to my second point.

Stats techniques play an outsized role in just those domains where theory is weakest. This is an old hobby horse of mine (see here for one example). Stats, especially fancy stats, induces the illusion that deep significant scientific insights are for the having if one just gets enough data points and learns to massage them correctly (and responsibly, no forking paths for me thank you very much). This conception is uncomfortable with the idea that there is no quick fix for ignorance. No amount of hard work, good ethics, or careful application suffices when we really have no idea what is going on. Why do I mention this? Because, in many of the domains where the replication crisis has been ripest are domains that are very very hard and where we really don’t have much of an understanding of what is happening. Or maybe to put this more gracefully, either the hypotheses of interest are too shallow and vague to be taken seriously (lots of social psych) or the effects of interest are the results of myriad interactions that are too hard to disentangle. In either case, stats will often provide an illusion of rigor while leading one down a forking garden path. Note, if this is right, then we have no problem seeing why psychometricians were in no need of the replication revolution. We really do have some good theory in the domains like sensory perception, and here stats have proven to be reliable and effective tools. The problem is not with stats, but with stats applied where they cannot be guided (and misapplications tamed) by significant theory.

Let me add two more codicils to this point.

First, here I part ways with AG. The post suggests that one source of the replication problem is with people having too great “an attachment to particular scientific theories or hypotheses.” But if I am right this is not the problem, at least not the problem behind the replication crisis. Being theoretically stubborn may make you wrong, but it is not clear why it makes your work shoddy. You get results you do not like and ignore them. That may or may not be bad. But with a modicum of honesty, the most stiff necked theoretician can appreciate that her/his favorite account, the one true theory, appears inconsistent with some data. I know whereof I speak, btw. The problem here, if there is one, is not generating misleading tests and non-replicable results, but if ignoring the (apparent) counter data. And this, though possibly a problem for an individual, may not be a problem for a field of inquiry as a whole. 

Second, there is a second temptation that today needs to be seriously resisted but that severely leads to replication problems: because of the ubiquity and availability of cheap “data” nowadays, the temptation to think that this time it’s different is very alluring. Big Data types often seem to think that get a large enough set of numbers, apply the right stats techniques (rinse and repeat) and out will plop The Truth. But this is wrong. Lars Syll puts it well here in a post entitled correctly “Why data is NOT enough to answer scientific questions”:

The central problem with present ‘machine learning’ and ‘big data’ hype is that so many –falsely- think that they can ge away with analyzing real-world phenomena without any (commitment to) theory. But –data never speaks for itself. Without a prior statistical set-up, there actually are no data at all to process. And – using a machine learning algorithm will only produce what you are looking for.

Clever data mining tricks are never enough to answer important scientific questions. Theory matters.

So, when one combines the fact that in many domains we have, at best, very weak theory, and that nowadays we are flooded with cheap available data the temptation to go hyper statistical can be overwhelming.

Let me put this another way. As AG notes, successful inquiry needs strong theory and careful measurement. Not the ‘and.’ Many read the ‘and’ as an ‘or’ and allow that strong theory can substitute for paucity of data or that tons of statistically curated data can substitute for virtual absence of significant theory. But this is a mistake. But a very tempting one if the alternative is having nothing much of interest or relevance to say at all. And this is what AG underplays: a central problem with stats is that it often tries to sell itself as allowing one to bypass the theory half of the conjunction. Further, because it “looks” technical and impressive (i.e. has a mathematical sheen) it leads to cargo cult science, scientific practice that looks "science" rather than being scientific. 

Note, this is not bad faith or corrupt practice (though there can be this as well). This stems from the desire to be, what AG dubs, a scientific “hero,” a disinterested searcher for the truth. The problem is not with the ambition, but the added supposition that any problem will yield to scientific inquiry if pursued conscientiously. Nope. Sorry. There are times when there is no obvious way to proceed because we have no idea how to proceed. And in these domains no matter how careful we are we are likely to find ourselves getting nowhere.

I think that there is a third source of the problem that resides in the complexity of the problems being studied. In particular, the fact that many phenomena we are interested in arise from the interaction of many causal sub-systems. When this happens there is bound to be a lot of sensitivity to the particular conditions of the experimental set up and so lots of opportunities for forking paths (i.e. p-hacking) stats (unintentional) abuse. 

Now, every domain of inquiry has this problem and needs to manage it. In the physical sciences this is done by (as Diogo once put it to me) “controlling the shit out of the experimental set up.” Physicists control for interaction effects by removing many (most) of the interfering factors. A good experiment requires creating a non-natural artificial environment in which problematic factors are managed via elimination. Diogo convinced me that one of the nice features of linguistic inquiry is that it is possible to “control the shit” out of the stimuli thereby vastly reducing noise generated by an experimental subject. At any rate, one way of getting around interaction effects problem is to manage the noise by simplifying the experimental set up and isolating the relevant causal sub-systems.

But often this cannot be done, among other reasons because we have no idea what the interacting subsystems are or how they function (think, for example, pragmatics).  Then we cannot simplify the set up and we will find that our experiments are often task dependent and very noisy. Stats offers a possible way out. In place of controlling the design of the set up the aim is to statistically manage (partial out) the noise. What seems to have been discovered (IMO, not surprisingly) is that this is very hard to do in the absence of relevant theory. You cannot control for the noise if you have no idea where it comes from or what is causing it. There is no such thing as a theory free lunch (or at least not a nutritious one). The revolution AG discusses, I believe, has rediscovered this bit of wisdom.

Let me end with an observation special to linguistics. There are parts of linguistics (syntax, large parts of phonology and morphology) where we are lucky in that the signal from the underlying mechanisms are remarkably strong in that they withstand all manner of secondary effects. Such data are, relatively speaking, very robust. So, for example, ECP or island or binding violations show few context effects. This does not mean to say that there are no effects at all of context wrt acceptability (Sprouse and Co. have shown that these do exist). But the main effect is usually easy to discern. We are lucky. Other domains of linguistic inquiry are far noisier (I mentioned pragmatics, but even large parts of semantics strike me as similar (maybe because it is hard to know where semantics ends and pragmatics begins)). I suspect that a good part of the success of linguistics can be traced to the fact that FL is largely insulated from the effects of the other cognitive subsystems it interacts with. As Jerry Fodor once observed (in his discussion of modularity), the degree to which a psych system is modular to that degree it is comprehensible. Some linguists have lucked out. But as we more and more study the interaction effects wrt language we will run into the same problems. If we are lucky, linguistic theory will help us avoid many of the pitfalls AG has noted and categorized. But there are no guarantees, sadly.



[1]I apologize for not being able to link to the original. It seems that in the post where I discussed it, I failed to link to the original and now cannot find it. It should have appeared in roughly June 2017, but I have not managed to track it down. Sorry.

Monday, June 25, 2018

Physics envy blues

These are rough days for those who suffer from Physics Envy (e.g. ME!!!!). It appears (at least if the fights in the popular press are any indication) that there is trouble in paradise and that physicists are beset with “ a growing sense of unease” (see herep. 1).[1]Why? Well for a variety of reasons it seems. For some (e.g. BA) the problem is that the Standard Theory in QM (ST) is unbelievably well grounded empirically (making “predictions verified to within one-in-ten-billion chance of error” (p.1)) and yet there are real questions that ST has no sway of addressing (e.g. “Where does gravity come from? Why do matter particles always possess three, ever heavier copies, with peculiar patterns in their masses, and why does the universe contain more matter than antimatter?” (p.1-2)). For others, the problem seems to be that physicists have become over obsessed with (mathematical) beauty and this has resulted in endless navel gazing and a failure to empirically justify the new theory (see here).[2]

I have no idea if this is correct. However, it is not a little amusing to note that it appears that part of the problem is that ST has just been too successful! No matter where we point the damn thing it gives the right empirical answer, up to 10 decimal points. What a pain!

And the other part of the problem is that it appears that the ways that theorists had hoped to do better (super-symmetry, string theory etc.) have not led to novel empirical results. 

In other words, the theory that we have that is very well grounded doesn’t answer questions to which we would love to have answers and the theories that provide potential answers to the questions we are interested in have little empirical backing. This hardly sounds like a crisis to me. Just the normal state of affairs when we have an excellent effective theory and are asking ever more fundamental questions. At any rate, it’s the kind of problem that I would love to see in linguistics.

However, this is not the way things are being perceived. Rather, the perception is that the old methods are running out steam and that this requires new methods to replace them. I’d like to say a word or two about this.

First off, there seems to be general agreement that the strategy of unification in which “science strives to explain seemingly disparate ‘surface’ phenomena by identifying, theorizing and ultimately proving their shared ‘bedrock’ origin” (BA;2) has been wildly successful heretofore. Or as BA puts in a more restrained manner, “has yielded many notable discoveries.” So the problem is not with the reasonable hope that such theorizing might bear fruit but with the fact that the current crop of ambitious attempts at unification have not been similarly fecund. Again as BA puts it: “It looks like the centuries-long quest for top-down unification has stalled…” (BA:2). 

Say that this is so. What is the alternative? Gelman in discussing similar issues titles a recent post “When does the quest for beauty lead science astray?” (here). The answer should be, IMO, never. It is never a bad idea to look for beautiful theories because beauty is what we attribute to theories that explain(i.e. have explanatory oomph) and as that is what we want from the sciences it can never be misleading to look for beautiful theories. Never.

However, beauty is not the onlything we want from our theories. We want empirical coverage as well. To be glib, that’s part of what makes science different from painting. Theories need empirical grounding in addition tobeauty. And sometimes you can increase a theory’s coverage at the expense of its looks and sometimes you can enhance its looks by narrowing its data coverage. All of this is old hat and if correct (and how could it be false really) then at any given time we want boththeories that are pretty and also cover a lot of empirical ground. Indeed, a good part of what makes a theory pretty is howit covers the empirical ground. Let me explain.

SH identifies (here) three dimensions of theoretical beauty: Simplicity, Naturalness and Elegance (I have capitalized them here as they are the three Graces of scientific inquiry).[3]

Theories are simple when they can “be derived from a few assumptions.” The fewer axioms the better. Unification (showing that two things that appear different are actually underlyingly the same) is a/the standard way of inducing simplicity. Note that theories with fewer axioms that cover the same empirical ground will necessarily have more intricate theorems to cover this ground. So simpler theories will have greater deductive structure, a feature necessary for explanatory oomph. There is nothing more scientifically satisfying than getting something for nothing (or, more accurately, getting two (better still some high N) for the price of one). As such, it is perfectly reasonable to prize simpler theories and treat them as evident marks of beauty.[4]

Furthermore, when it comes to simplicity it is possible to glimpse what makes it such a virtue in a scientific context. Simpler theories not only have greater deductive structure, the are also better grounded empirically in the sense that the fewer the axioms, the more empirical weight each of them supports. You can give a Bayesian rendition of this truism, but it is intuitively evident. 

The second dimension of theoretical beauty is Naturalness. As SH points out, naturalness is an assumption about types of assumptions, not the number. This turns out to be a notion best unpacked in a particular scientific local. So, for example, one reason Chomsky likes to mention “computational” properties when talking about FL is that Gs are computational systems so computational considerations should seem natural.[5]Breakthroughs come when we are able to import notions from one domain into another and make them natural. That is why a good chunk of Gallistel’s arguments against neural nets and for classical computational architectures amounts to arguing that classical CS notions should be imported into cog-neuro and that we should be looking to see how these primitives fit into our neuro picture of the brain. The argument with the connectionist/neural net types revolves around how natural a fit there is between the digital conception of the brain that comes from CS and the physical conception that we get out from neuroscience. So, naturalness is a big deal, but it requires lots of local knowledge to get a grip. Natural needs an index. Or, to put this negatively, natural talk gets very windy unless grounded in a particular problem or domain of inquiry.

The last feature of beauty is Elegance. SH notes that this is the fuzziest of the three. It is closely associated with the “aha-effect” (i.e. explanatory oomph). It lives in the “unexpected” connections a theory can deliver (a classic case being Dirac’s discovery of anti-matter). SH notes that it is also closely connected to a theory’s “rigidity” (what I think is better described as brittleness). Elegant theories are not labile or complaisant. They stand their ground and break when bent. Indeed, it is in virtue of a theory’s rigidity/brittleness that it succeeds having a rich deductive structure and explanatory oomph. Why so? Because the more brittle/rigid a theory is the less room it has for accommodating alternatives and the less things a theory makes possiblethe more it explains when what it allows as possible is discovered to be actual.

We see this in linguistics all the time. It is an excellent argument in favor of one analysis A over another B that A implies C (i.e. A and not-C are in contradiction) whereas B is merely consistent with C (i.e. A and not-C are consistent). A less rigid B is less explanatory than a more rigid A and hence is the superior explanatoryaccount. Note that this reasoning makes sense onlyif one is looking at a theory’s explanatory features. By assumption, a more labile account can cover the same empirical ground as a more brittle one. The difference is in what they excludenot what they cover. Sadly, IMO, the lack of appreciation of the difference between ‘covering the data’ and ‘explaining it’ often leads practitioners to favor “flexible” theories, when just the opposite should be the case. This makes sense if one takes the primary virtue of a theory to be regimented description. It makes no sense at all if one’s aims lie with explanation.

SH’s observations make it clear (at least to me) why theoretical beauty is prized and why we should be pursuing theories that have it. However, I think that there is something missing from SH’s account (and, IMO, Gelman’s discussion of it (here)). It doesn’t bind the three theoretical Graces as explicitly to the notion of explanation as it should. I have tried to do this a little in the comments above, but let me say a bit more, or say the same things one more time in perhaps a slightly different way.

Science is more than listing facts. It trucks in explanations. Furthermore, explanations are tied to the why-questions that identify problems that explanations are in service of elucidating. Beauty is a necessary ingredient in any answer to a why-question but what counts as beautiful will heavily depend on what the particular question at issue is. What makes beauty hard to pin down is this problem/why-question relativity. We want simple theories, but not toosimple? What is the measure? Well, stories just as complicated as required to answer the why-question at issue. Ditto with natural. Natural in one domain wrt to one question might be unnatural in another wrt to a different question. And of course the same is the case with brittle. Nobody wants a theory that is so brittle that it is immediately proven false. However, if one’s aim is explanation then beauty will be relevant and what counts as beautifulwill be contestable and rightly contested. In fact, most theorizing is argument over how to interpret Simple, Natural and Elegant in the domain of inquiry. That’s what makes it so important to understand the subtleties of the core questions (e.g. in linguistics: Why linguistic creativity? Why linguistic promiscuity? How did FL/UG arise?). At the end of the day (and, IMO, also at sunrise, high noon and sunset) the value of one’s efforts must be judged against how well the core questions of the discipline have been elucidated and their core problems explained. And this is a messy and difficult business. There is no way around this.

Actually, this is wrong. There is a way around this. One can confuse science with technology and replace explanation with data regimentation and coverage. There is a lot of that going around nowadays in the guise of Big Data and Deep Learning (see hereand here). Indeed some are calling for a revamped view of what the aim of science ought to be; simulation replacing explanation and embracing the obscurantism of overly complex uninterpretable “explanations.” For these kinds of views, theoretical beauty really is a sideshow. 

At any rate, let me end by reiterating the main point: beauty matters, it is always worth pursuing, it is question relative and cannot really ever be overdone. However, there is no guarantee that the questions we most want answered can be, or that the methods we have used successfully till now will continue to be fruitful. It seems that physicists feel that they are in a rut and that much of what they do is not getting traction. I know how they feel. But why expect otherwise? And what alternative is there to looking for beautiful accounts that cover reasonable amounts of data in interesting and enlightening ways? 


[1]This post is by Ben Allanch from Cambridge University physicist. I will refer to this post as ‘BA.’
[2]Sabine Hossenfelder (SH) has written a new book on this topic Lost in Maththat is getting a lot of play in the popular science blogosphere lately. Hereis a strong recommendation from one of our own Shravan Vasishth who believes that “she deserves to be world famous” for her views. 
[3]The Three Graces were beauty/youth, mirth and elegance (see here). This is not a bad fit with our three. Learning from the ancients, it strikes me that adding “mirth” to the catalogue of theoretical virtues would be a good idea. We not only want beautiful theories, we should also aim for ones that delight and make one smile. Great theories are not somber. Rather they tickle one’s fancy and even occasionally generate a fat smile, an “ah damn” shake of the head and a feeling of overall good feeling. 
[4]SH contrasts this discussion of simplicity with Occam’s claiming that the latter is the injunction to choose the simpler of two accounts that cover the same ground. The conception SH endorses is “absolute simplicity,” not a relative one. I frankly do not understand what this means. Unification makes sense as a strategy because it leads to a simpler theory relative to the non-unified one. Maybe what SH is pointing to is the absence of the ceteris paribus clause in the absolute notion of simplicity. If so, then SH is making the point we noted above: simpler theories might be empirically more challenged and in such circumstances Occam offers little guidance. This is correct. There is no magic formula for deciding what to opt for in such circumstances, which is why Occam is such a poor decision rule most of the time.
[5]See his discussion of Subjacency in On Wh Movementfor example.

Friday, June 30, 2017

Statistical obscurantism; math destruction take 2

I've mentioned before that statistical knowledge can be a dangerous thing (see here). It's a little like Kabbala, something that is dangerous in the hands of inexperienced, the ambitious and lazy.  This does not mean that in its place stats are not valuable tools. Of course they are. But there is a reason for the slogan "lies, damn lies and statistics." A few numbers can cover up the most awful thinking, sort of like pretty pix of brains in the NYT can sell almost any new cockamamie idea in cog-neuro. So, in my view, stats is a little like nitroglycerine; useful but dangerous on unsteady ground.

Now, even I don't really respect my views on these matters. What the hell do I know, really? Well, very little. So I will buck this view up by pointing you to an acknowledged expert on the subject who has come to a very similar conclusion. Here is Andrew Gelman despairing of the view that done right stats is the magic empirical elixir, able to get something out of any data set, able to spin scientific gold from any experimental foray:

In some sense, the biggest problem with statistics in science is not that scientists don’t know statistics, but that they’re relying on statistics in the first place.
How is stats the problem? Because it covers up dreadful thinking:
Just imagine if papers such as himmicanes, air rage, ages-ending-in-9, and other clickbait cargo-cult science had to stand on their own two feet, without relying on p-values—that is, statistics—to back up their claims. Then we wouldn’t be in this mess in the first place.
So, one problem with stats is that they can make drek look serious. Is this a problem with the good use of stats? No, but given the current culture, it is a problem. And as these pair of quotes suggests, if something absent the stats sounds dumb, then one should be very very very wary of the stats. In fact, one might go further: if the idea sans stats looks dumb then the best reaction on hearing that idea with stats is to reach for your wallet (ore your credulity).

So what does Gelman suggest we do? Well, he is a reasonable man so he says reasonable things:
I’m not saying statistics are a bad idea. I do applied statistics for a living. But I think that if researchers want to solve the reproducibility crisis, they should be doing experiments that can successfully be reproduced—and that involves getting better measurements and better theories, not rearranging the data on the deck of the Titanic.
Yup, it looks like he is recommending thinking. Not a bad idea.  The problem is that stats has the unfortunate tendency of replacing thought. It gives the illusion of being able to substitute technique for insight. Stats are often treated as the Empiricist's perfect tool: it is the method that allows the data speak for itself. And this is the illusion that Gelman is trying to puncture.

German has (given his posts of late) come to believe that this illusion is deeply desired. Here he is again replying to the suggestion that misuse of stats is largely an educational problem:
Not understanding statistics is part of it, but another part is that people—applied researchers and also many professional statisticians—want statistics to do things it just can’t do. “Statistical significance” satisfies a real demand for certainty in the face of noise. It’s hard to teach people to accept uncertainty. I agree that we should try, but it’s tough, as so many of the incentives of publication and publicity go in the other direction.
I would add, you will not be surprised to hear, that there is also the Eish dream I mentioned above wherein the aim is to minimize the human factor mediating data and theory. Rationalists believe that the world must be vigorously interrogated (sometimes put under extreme duress) to reveal its deep secrets. Es don't think that it has deep secrets as they don't really believe that the world has that much hidden structure. Rather the problem is with us: we fail to see what is before our eyes if we gather the data carefully and inspect it with an open heart. The data will speak for itself (which is what stats correctly applied will allow it to do). This Eish vision has its charms. I never underestimate it. I think that it partially lies behind the failure to appreciate Gelman's points.