Mike the Mad Biologist

It really does matter: if economists are going to use biology as a model for their discipline, we need them to understand ours, to help improve theirs. But I’m getting ahead of myself.

By way of Brad DeLong, we stumble across this Russ Roberts piece discussing the question of what kind of science (if any) is economics. What bothered me in reading the original piece was how badly the biology was mangled (which doesn’t give me much hope for economics). Let’s go to Roberts (italics mine):

I have often said that economics, to the extent it is a science, is like biology rather than physics. Let me try to make that clearer. By biology, I do not mean the study of the human cell, which we have made a great deal of progress understanding though there is more to learn. I am thinking of biology in the sense of an ecosystem where competition and emergent order create a complex interaction of organisms and their environment. That sounds a lot like economics and of course it is. But we would never ask of biologists what the public and media ask of economists. We do not expect a biologist to forecast how many squirrels will be alive in ten years if we increase the number of trees in the United States by 20%. A biologist would laugh at you. But that is what people ask of economists all the time. Economists should be honest and say that the tasks they are often asked to do are outside the scope of economics as we know it and perhaps outside the scope of economics as it will ever be known.

Erm, no. Actually, ecologists not only answer those types of questions for regulatory purposes all the time (e.g., forestry biologists, fisheries biologists, pest control, crop management), but they routinely answer much more difficult questions, such as how does a temperature increase combined with less rainfall affect pine populations due to a change in bark beetle populations. Biologists have been running simulations (which are different from models) for a very long time.

Onto the subject of evolution (italics mine):

Is economics a science because it is like Darwinian biology? Darwinian biology is very different from the physical sciences. Like economics it is a very useful way to organize your thinking about complex phenomena. But it is not a predictive or very precise science or whatever you want to call it. Before seeing any direct fossil evidence, no biologist can tell you how long the giraffe’s neck was ten million years ago. They cannot make accurate backcasts of any precision such as the year that the forerunner of the giraffe began to lengthen its neck through natural selection. It cannot model why the giraffe’s neck isn’t longer. Darwinism, like much of economics, exploits tautological reasoning. If the fossil record is incomplete or shows no change or vast periods or the pace of change is inconsistent with the fossil record, the theory is not discarded but modified with the concept of punctuated equilibrium. Is punctuated equilibrium true? There is no real way of knowing. It is our best hypothesis given very limited data. Is it a science? Sure. But it is a science that is unlike physics. That’s OK. It is still a very useful way of organizing one’s thinking about evolution. And the “imperfection” of biology is fine unless you really want to know when the elephant got his trunk. Then you are in unscientific territory. It doesn’t matter whether our understanding of natural selection is imperfect or that we simply don’t have enough fossil data. Biologists understand the limits of their field.

Whenever you hear the term ‘Darwinian’ from anyone other than historians of science, assume the crash position; it’s going to get real ugly. There’s a lot here to correct (but we like helping!). First, evolutionary biologists do predict past states: whenever we reconstruct evolutionary histories (phylogenies), we reconstruct the ancestral past states. And if we have molecular data, we can often attach a rough estimate of time to those states. We certainly can get the order in which events occurred estimated reliably.

The part about tautology is an egregious misunderstanding of the theorem of natural selection. The theorem of natural selection is, well, a theorem because it is repeatedly supported by multiple, independent lines of evidence. The punctuated equilibrium hypothesis isn’t a theorem. It is simply a testable prediction of how the outcome of natural selection should be reflected in the fossil record. Sometimes ‘punk eek’ does fit the observed data, and sometimes it doesn’t. This is what one expect of a discipline that deals with historical contigency–as does economics. As a dissertation committee member once told me, “It all comes down to those stupid fucking natural history facts.”

But where Roberts goes off the rails is his statement that economists try to predict specifics and that’s impossible to do. I personally wouldn’t blame an economist who didn’t get the timing exactly right on the collapse of Big Shitpile. But what was disturbing was that very few economists–or at least those that interacted with the public–were saying that the combination of rapidly rising housing prices, high personal debt and stagnating wages were a disaster waiting to happen. Contrast that with how evolutionary biologists approached the problem of antibiotic resistance in bacteria. Bruce Levin and Frank Stewart published the first population genetics treatment of the evolution of resistance. In 1977. Whenever I’ve explained to evolutionary biologists who are unfamiliar with microbiology that:

1) We are bathing the world in a dilute solution of antibiotics (to use Julian Davies’ phrase);

2) Bacteria can evolve heritable resistance.

–the response has always been ~~Oh God, Oh God, we’re all gonna die~~ that it’s obvious resistance would increase in a global sense. Predicting which beta-lactamase resistance allele would be seen first in a particular hospital is far more difficult (although Dan Weinreich has done some very nice work on that question). But the failure to predict the housing crisis isn’t equivalent to getting the specific adaptive change involved in a particular case of resistance wrong; it’s the equivalent of saying, “Don’t worry, be happy” because resistance won’t evolve. I’ll forgive missing the specific, but the general outlines should be correct.

Then there’s the role of historical contingency. A lot of events in biology–and I would argue economics too–are dependent on those stupid natural history facts. In this sense, biology and economics are sciences in the way that astrophysics is a science: while general theory can give you some idea of how things could work, you need to know some natural history, some facts, to understand how things do work:

…biologists aren’t only trying to derive general principles, they’re also trying to figure out how organism- or system-specific processes work.

To use a very macabre example, we are interested in a how a gun fires a bullet–and in a controlled environment, we can estimate very precisely how that bullet will travel. But, a biologist is also faced with the task of trying to figure out what happened on the grassy knoll in Dallas. The study of ballistics is necessary, but not sufficient. At the risk of completely tasteless overkill, does anyone view September 11th primarily (or even entirely) as a structural engineering problem? Those stupid natural history facts matter too. Understanding and predicting particular events also requires a knowledge of phenomena that can not be generalized and reduced to simple general theory.

(also see this)

That leads to another issue, which is that economics has to be viewed in part as a social science. Some of the phenomena that drive economic behavior really need a good sociologist, not a mathematician.

But the really key difference is that biology has accepted modes of confronting theories and, importantly, discarding them. As Paul Krugman notes, that doesn’t seem to be happening:

Yes, the old Keynesian Phillips curve was abandoned in the face of evidence. But while real business cycle theory has indeed been “invalidated by reality”, as far as I can tell it’s still going strong in freshwater departments.

The point is that while economics certainly did have some of the characteristics of a science three decades ago, you can make a good case that significant parts of the field have lost those characteristics since then.

I want to end with something Barry Eichengreen wrote:

The late twentieth century was the heyday of deductive economics. Talented and facile theorists set the intellectual agenda. Their very facility enabled them to build models with virtually any implication, which meant that policy makers could pick and choose at their convenience. Theory turned out to be too malleable, in other words, to provide reliable guidance for policy.

In contrast, the twenty-first century will be the age of inductive economics, when empiricists hold sway and advice is grounded in concrete observation of markets and their inhabitants. Work in economics, including the abstract model building in which theorists engage, will be guided more powerfully by this real-world observation. It is about time.

Should this reassure us that we can avoid another crisis? Alas, there is no such certainty. The only way of being certain that one will not fall down the stairs is to not get out of bed. But at least economists, having observed the history of accidents, will no longer recommend removing the handrail.

That sounds a lot like modern biology. Including the ‘Darwinist’ stuff.

Update: Brad DeLong has some interesting thoughts on economics as a discipline.

Comments

#1 kevin denny
March 21, 2011

Your rant would be rather more interesting if one knew that you were addressing the general views of economists rather than just one.
I doubt if Russ Roberts’ views are typical of how economists think about biology because in general economists don’t think about biology at all. A shame perhaps, but true.
That you don’t have much hope for economics on the basis of one observation suggests a shaky knowledge of statistics to me.
#2 Ed Darrell
March 21, 2011

First, I would observe that Russ Roberts’ argument is close enough to the same argument Marx (and Engels) made, essentially, based on his reading of Darwin. Human enterprises are in constant flux, with constant variation, and competition determines what happens. One of Marx’s errors was to try to restrict that competition to a “dialectic” between two or not-many-more ideas in the political/economic sphere.

But it’s odd, to me, to see Roberts making Marx’s argument without attribution. Roberts is no Marxist; one would think he would need to distinguish his use of the biology analogy or capitalist economists would howl him down. Watch to see whether any do — it may be a sad indication that these guys haven’t read Marx, nor Darwin, and don’t know the key ideas, and of course can’t really discuss in any serious way why the ideas are good or bad in any particular circumstance.

Were it a science paper, someone would ask him (in peer review, we hope) to explain how his assumption differs from Marx’s, and why all the usual criticism applied to Marx does not apply to Roberts. Too much for us to hope for, here.

But, second, while I disagree on the surface with your reading of Roberts, I’m surprised he didn’t take it to the logical conclusions that are really warranted.

No, ecologists and wildlife managers wouldn’t dare predict how many squirrels there will be in 20 years based on the number of trees alive then — but they will tell you with some certainty that there will be more than present, if adequate tree habitats are expanded, or fewer than present, if habitats are contracted or otherwise rendered less than capable of supporting the measure population.

In other words, biologists, with proper attention paid to evolutionary pressures as you accurate and carefully note, will tell policy makers that it’s a bad idea to continue decreasing habitat for painted buntings in North and Central Texas, if we do not wish to see the bird extinct, soon, and they will be right. Moreover, they will be able to predict with some accuracy how many birds exist now, if careful counting is done, and predict with great accuracy whether the populations will expand or contract if they can gather information on enough variables. See for example the work of Peter and Rosemary Grant, in which they tracked every individual in three species on an isolated island, for more than 30 years. Eventually they had enough data so that a student of theirs constructed a computer program that would indeed predict evolution of the species, depending on rainfall in a given year. And the predictions were accurate.

It’s an issue of having enough data, and understanding the processes. Recent Nobels have gone to people who have pointed out that many economists have regarded their profession more as chemistry, and they have failed to gather enough information on how the principal biological entities in economics actually work. That is, that humans do not always act rationally when they spend a buck.

Excellent catch, Ed Brayton. Thanks.
#3 Ed Darrell
March 21, 2011

Rereading your piece, I take less issue with any part of it. But I still think you’ve done Dr. Roberts a great favor to point out some of the egregious errors he has taken on with his assumption.

In other words, great work, Ed.
#4 hibob
March 21, 2011

“But what was disturbing was that very few economists–or at least those that interacted with the public–were saying that the combination of rapidly rising housing prices, high personal debt and stagnating wages were a disaster waiting to happen. Contrast that with how evolutionary biologists approached the problem of antibiotic resistance in bacteria. ”

I think the main difference wasn’t in the models/simulations; it was in the motives. The vast majority of economists during the boom were paid for a service, and that service was decidedly NOT to predict the demise of big shitpile. The paying gigs available to those willing to rubber stamp every new class of derivative that came their way as a sound investment vastly outnumbered those available to Cassandras. If you were willing to pay attention, you could still find plenty of economists who were pointing out that the boom was heading for a bust back in 2005, but that trait was decidedly selected against. You could also go back and read the original papers that described the valuation models used by those who created the derivative economy, and note the comments by the authors saying that the models really weren’t suitable for the type of security market that begat big shitpile.

On the other hand, imagine if most of the biologists accessible to the public were employees of companies that manufacture antibiotics, and most of the rest consulted for those companies, received honoraria, endowed chairs, etc. Furthermore stipulate that compensation in the companies was tied to quarterly goals and that the patents on the antibiotics would be running out fairly soon, so the companies had no financial incentive to preserve existing antibiotic efficacy. You’d end up with the same type of situation: a few biologists pointing out the problem, and the vast majority ignoring it.
#5 michi
March 21, 2011

the statistics of the whole is well designed, and also has a sense who you are all neutral look great work the whole piece. I rarely read something great

great work, michi
#6 mike kimel
March 21, 2011

I am an economist. I do not believe economics is a science and it is because of economists. No physicist or biologist is going to take seriously someone whose beliefs about the field are completely contradicted by the data. In economics, on the other hand, there doesn’t seem to be any penalty for building models for which almost every observation is a special case. Complete unfamiliarity with the data is not considered a problem. Result- magical thinking. We’re where astronomy was before Tycho Brahe.
#7 TTT
March 21, 2011

[Darwinism] is not a predictive or very precise science or whatever you want to call it. Before seeing any direct fossil evidence, no biologist can tell you how long the giraffe’s neck was ten million years ago. They cannot make accurate backcasts of any precision

Except when they can, as was the case with Darwin’s moth and Ambulocetus and every other instance that Roberts never heard of because he’s a dilettante and out of his league.

Few people misunderstand environmental biology as badly as economists do. I have had professional, lettered economists tell me that such-and-such species will never be hunted to extinction because it would be more in the self-interest of consumers to set up sustainable markets for them–because a population that ritualistically eats totem animal body parts because of some pre-civilizational belief in spirit power transfer is very well-read on their supply curves. And let’s not even get into that 9.0-magnitude kook Julian Simon and all of his neo-alchemist acolytes….
#8 David O.
March 21, 2011

What a lovely rant. Well done. I really really hope it has been brought to the attention of – at least – Brad DeLong and Paul Krugman… But I doubt the Freshwater guys would be at all interested.
#9 abb3w
March 21, 2011

Mike: But the really key difference is that biology has accepted modes of confronting theories and, importantly, discarding them.

My impression is that economics is at one of those transitional phases that sciences go through. I’m most familiar with examples from physics; EG, the period between the “it’s not there” MM ether experiment and Einstein’s Annus Mirabulis. For about 20 years, it was quite clear that the theoretical model of the Aether hypothesis was wrong; however, people kept using it despite the clear flaws, because no-one had come up with and presented a better mathematical model. (To a lesser extent, the Plum Pudding model’s supplanting by the Bohr Model is similar.)

It’s not enough for the pre-existing model (or as Kuhnians might have it, “paradigm”) to be broken. Even broken, it may still be better for many purposes than no model at all (or rather, purely “gut instinct” models). Before it seriously starts fading away, you first need a replacement.

Of course, once the replacement comes along, you then have to deal with the difference between science as elegant philosophical ideal versus ugly anthropological practice. Humans don’t change their minds instantaneously, especially after committing extensive time and effort to some approach. With rare exceptions, people’s habits of thought tend to ossify over time. Thus, even after some Bright Young F*cker comes up with a better model (and even collects his Nobel for it), there will be a cantankerous old guard who stick with the Chicago school, just as some old guard resisted Einstein’s Relativity, and as he in turn had issues with QM. As Max Planck cynically put it, “A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.” Or his more succinct cynicism: “Science progresses one funeral at a time.”

That said, there seem to be some youngish economists looking for improved models. (Dan Ariely seems to have his head on fairly straight; possibly because his degree and training aren’t in economics.) We probably also need more funerals, however.
#10 abb3w
March 21, 2011

s/ ether / Aether /

Sigh…
#11 Ed Darrell
March 21, 2011

Mike, my apologies.

I was distracted this morning when I read your great stuff on Roberts’ column. I thought I was reading Ed Brayton’s blog.

My apologies.

Great work, Mike. Sheesh. Maybe you could go back to my earlier posts and edit them . . .
#12 blueshift
March 21, 2011

I don’t see any italics in the second block quote?
#13 Richard Simons
March 21, 2011

“But what was disturbing was that very few economists–or at least those that interacted with the public–were saying that the combination of rapidly rising housing prices, high personal debt and stagnating wages were a disaster waiting to happen.”

Is this correct? I am not arguing with you, but about a year before the crisis I remember discussing this (and the deferred interest problem) with the business education instructor at the place where I was teaching basic science/maths. If it was obvious to me I would expect it to be obvious to people working in that area.
#14 brainwashedevolutionist
March 22, 2011

Hopefully economists will steer clear of modeling after any aspect of a failing theory. The brainwashing that has taken place in the name of science will take generations to undue and progress will be hindered due to the simple-minded biologist who replace scientific method with political idealism. Go pray to whatever theory is the flavor of the week and cling to your fancy drawings and entertaining mythology. Leave science alone and allow impressionable children to look at the things called facts rather than be indoctrinated by pseudo-scientific cultists.
#15 David Marjanović
March 22, 2011

I hope this won’t be posted twice.

The theorem of natural selection is, well, a theorem

I wouldn’t call anything outside of mathematics a theorem. Evolution by mutation, selection & drift is a theory.

Before seeing any direct fossil evidence, no biologist can tell you how long the giraffe’s neck was ten million years ago.

Not by looking just at the giraffe. Add an okapi and a deer, and just enough fossils to calibrate the tree in time (necks don’t need to be preserved), and there you go.

And yes, reconstructing ancestors is part of the algorithms that are used to reconstruct phylogenetic trees. You can’t have one without the other.
#16 antifia
March 22, 2011

Physiocrats were a common breed of economists about two centuries ago – I thought they were extinct these days.
Anyway, if economics had any semblance to biology, most of us economists wouldn’t be able to tell it – people that study economics in college tend not to be the same people who enjoyed their high-school biology classes.
#17 JakeS
March 22, 2011

The core problem for the central tradition in economics is that the entire edifice is constructed upside-down. The models begin by assuming that which is most difficult to measure – human motivation – and then goes on to construct an entire language in which to talk about their assumptions about human motivation. A more sensible approach would be to begin with that which is easiest to measure – actual production and transaction events – construct a language to talk about those, and then run a gamut of behavioural models through that language. The latter would provide a much more robust theory.

Less charitably, the problem is that all the people who had understood the implications of the Great Depression went and did useful things with their time and knowledge. While all the people who failed to understand the Great Depression – having, by and large, no useful skills to contribute to society – spent their time constructing an elaborate mathematical obfuscation around the fact that they were unwilling to abandon their Ricardian magic pony models.

- Jake
#18 Marion Delgado
March 22, 2011

Paul Krugman quite a long time ago did a completely brain-dead essay simultaneously attacking John Kenneth Galbraith and Stephen Jay Gould – easily as dumb as the above.
#19 Marion Delgado
March 22, 2011

TTT I’ll see your Julian Simon and raise you a Bob Truax (admittedly an acolyte, not a priest) who said the Earth could sustain a population of a septillion people with “no discernable environmental impact.” (When everyone like Simon knew the proper number was “several trillion”).
#20 Ken
March 22, 2011

From the Barry Eichengreen quote: Work in economics, including the abstract model building in which theorists engage, will be guided more powerfully by this real-world observation. It is about time.

In some ways it’s worse than that; many economic theories are based on assumptions that are in contradiction to the real-world observations. See http://www.nakedcapitalism.com/2011/02/exclusive-harvard-economists-prove-that-bankruptcy-is-mythical.html for actual examples.

Please note, the delivery of that article is pure sarcasm, but the particulars of its statements about economic theories are true – for example, that many theories require assuming “all individuals and corporations can borrow unlimited amounts of money at the risk-free rate”. The punchline is that those theorems, such as Black-Scholes, are built into the systems and programs that do the pricing and trading for the companies managing your 401K.

The only analogy I can think of from biology is Lysenko. I suppose there are a few examples from applied biology and medicine (cough cough homeopathy cough). I wonder if that means the root cause is judging your theory by whether you can make money selling it, not whether it agrees with the real-world observations.
#21 Mike Magee
March 22, 2011

Some economists knew we were heading for a bust in 2005, eh? Yet all of them had seen Orange County go bust in 1994 from exactly the same faith in derivatives that caused the big bust in 2008. Michael Moore, neither a biologist nor an economist, featured it in his 1996 book “Downsizing”.

The truth is that there was nothing scientific about it — science has to be objective — and economists were in it for the ride as much as the bankers and financiers. Nothing significant seems to have changed. Unless all those greedy twerps accept proper control and taxation, and realize that society is what counts not who is the richest man in the world, then it will happen again, and worse!
#22 steve from virginia
March 22, 2011

Pretty funny, another scientist running away screaming from any association with economics.

Can’t say I blame Mike the Mad: a problem with economics and economists is they desire the reputability and high sheen of something or other that falls to scientists without having to accept science’s curiosity.

Russ Robert’s piece is from Cafe Hayek, should have known … economics is all curve- fitting and reverse engineering. Economics is more like selling insurance or used cars rather than biology.

Another problem is the economic emphasis on prediction which is an out-take of divination or haruspices which is the interpretation of animal innards (which is not biology although I do remember the frog innards from … Mr Mohler’s biology class

Economists won’t admit to what is taking place under their noses, forget about the predictions they miss.

Current economic thinking is a form of public relations.

Period.
#23 Greg Ransom
March 22, 2011

Macroeconomists working under the influence of Hayek — like BIS chief economists William White — were explaining this stuff, to people like Alan Greenspan and the leading Fed macroeconomists.

See, for example, this:

http://hayekcenter.org/?p=444

You wrote,

“But what was disturbing was that very few economists–or at least those that interacted with the public–were saying that the combination of rapidly rising housing prices, high personal debt and stagnating wages were a disaster waiting to happen.”
#24 Greg Ransom
March 22, 2011

I explain the parallel between the explanatory strategy of economics and Darwinian biology (exploiting the accounts of Mayr & Hayek) in the 2nd half of the paper here:

http://www.hayekcenter.org/friedrichhayek/hayekmyth.htm

I show why there are insuperable limits to reduction — and prediction — in Darwinian biology here:

http://hayekcenter.org/ransompapers/Limits_to_Reduction.html

The first paper was written at the invitation of Bruce Caldwell, the second was written for Alex Rosenberg and Larry Wright. Note that Rosenberg has taken up some of these themes in later work.
#25 Greg Ransom
March 22, 2011

Here is the parallel (in brief) between Darwinian biology and economic science (as outlined in Mayr & Hayek).

Both begin with the casting of problem raising patterns of design-like order in our experience, and both are explained by an open-ended causal mechanism involving context-dependent functional types which are closed or “carved at the joint” in terms of lower level natural kinds.

The principle causal mechanism in Darwinian biology is natural selection (among other selection mechanism).

The principle causal mechanism in economics is changing entrepreneurial judgments in the context of changing relative prices and local conditions.

The question raising patterned order which needs explaining in Darwinian biology is the conjoined phenomena of functional adaptation and the origin of species.

The dominant question raising pattern in economics is the pattern where prices tend toward costs of production conjoined with the observation of the large-scale general coordination of individual production and consumption plans.

Both of these explanation are what Hayek called “explanations of the principle” — in his papers “Degrees of Explanation” and “The Theory of Complex Phenomena” and in his book _The Sensory Order_ (ask Joaquin Fuster or Gerald Edelman).

Hayek’s account of “essentially complex phenomena” and his account of Darwinian biology, global brain theory, and economics as sciences of “the principle” forced Karl Popper to conceded that his falsifiability criterion of “science” had been falsified by the counter-example of these sciences (see Popper’s autobiography).

Popper has said that he learned more from Hayek than anyone, excepting only Tarski.
#26 Greg Ransom
March 22, 2011

To sum up.

Both economics and Darwinian biology provide contingent causal explanation for functional patterns and patterns with design-like characteristics.

(For more on the character of teleological explanation, see Larry Wright, _Teleological Explanation_ and Alexander Rosenberg, _The Structure of Biological Science_).

Both economics and Darwinian biology involve the direct perception of functional and goal-directed phenomena and order-revealing patterns — patterns which cry out for underlying causal mechanism explanation, when cast in the correct light (as by Darwin & Mayr and Hayek & Smith).

And these functionally and teleologically defined categories are open-ended and cannot be pre-defined (cut at the joint in terms of natural kinds) outside the unfolding of history.

See on this F. A. Hayek, _The Counter-Revolution of Science_ and my paper “Insuperable Limits to Reduction in Biology”).
#27 Greg Ransom
March 22, 2011

Right — arguments made by Nobel Prize winning economist and brain theorist Friedrich Hayek in a series of books (_The Sensory Order_, _The Counter-Revolution of Science_, _The Pure Theory of Capital_) and papers (“Degrees of Explanation”, “The Theory of Complex Phenomena”, “The Primacy of the Abstract”,among many others.)

And arguments made in my paper “Hayek’s Copernican Revolution in Economics” and “Insuperable Limits to Reduction in Biology” available at http://hayekcenter.org

Mike wrote,

“In this sense, biology and economics are sciences in the way that astrophysics is a science: while general theory can give you some idea of how things could work, you need to know some natural history, some facts, to understand how things do work.”
#28 Nomen Nescio
March 22, 2011

greg ransom, are you a historian of science?
#29 Benign Brodwicz
March 22, 2011

Academic economists are ideological cheerleaders. They don’t do science, they do propaganda.

Disclosure: I am an ex-academic economist, now in business.
#30 Robert Waldmann
March 23, 2011

I am an economist and an ex biologist (BA and began PhD in Biology). I do think that Roberts has a point — economists have to get over physics envy. It is a plain fact that the only natural science which comes to most econmists minds is physics (this is my experience basically without exception).

This means that economists identify scientifit thought with thought involving math. I’m not sure if Roberts knows enough to understand this, but he chose examples from fields of biology in which math is used. In contrast much work in molecular and cellular biology isn’t mathematical at all — the models are drawings not equations. Some economists just don’t grasp how rigorous can be separate from mathematical.

Very importantly economic theory has status in the profession totally aside from its relationship with data. It is taught as math and appreciated as math. The question of whether it corresponds to reality is considered by some to be naive. “Theory” is identified with “models” and models are false by definition. A prediction is derived from a hypothesis of interest and some auxiliary hypotheses. It is tested. It is rejected by the data. This has no effect on anything. It is concluded either that the problem is with the auxiliary hypotheses (which are still regularly assumed when developing models including models used to guide policy). Or econmists just note that the alleged hypothesis of interest isn’t really a hypothesis since we all were always sure it is false and so what ?

As far I as can recall, that hasn’t happened in biology in centuries (that is since it was based on the four humors).

Now here I can see some good coming from Roberts’s analogy. The theory which is used in spite of total empirical failure is considered necessary for rigor (meaning mathematical not scientific). The invalid reasoning is that looks sort of like physics, so economics has to be like that to be a science.

Biologists have achieved great things empirically step by step (with the occasional BS speculation about evolution, because that gives the work theoretical dignity). There are economists doing the same, with empirical work using assumptions (sometimes that an experiment is related to a real world phenomenon sometimes that a real world pheonomenon is a natural experiment) which seem obviously true to non economists (and economists including me). Their status in the profession is rapidly rising. I mean economics is getting to be a lot more like biology than it was 25 years ago. It’s beginning to have the feature that you can’t get published for being cleaver and you have to actually work (yes I am thinking of moving on to some less scientific field).

The stuff below is really boring.

Roberts also is very wrong as you note. Here I am ignorant too (I was a microbiologist not an ecologist or evolutionary biologist — I used no math at work which is part of why I couldn’t stand it (biological research that is– I like math)). Also I am just agreeing with length with what you wrote.

Roberts clearly doesn’t know much about research in ecology. You bet that “Darwinism” is a warning sign. He doesn’t have a clue about what one can predict using the theory of evolution by natural selection, how much has been predicted, the confrontation of those predictions and data or just how utterly nonsensical to compare evolutionary biology to economics. Here a large part of the problem is that the predictions concern trivial things (hence analogous not homologous). Enough to prove that Darwin was on to something, but who cares about the sequences of introns.

Also, Gould was a rhetorical genius. The key success of punctuated equilibrium theorists was setting up straw men. They really were debating Darwin (Huxley was on their side — I learned this from one of Gould’s books). Economics hasn’t failed in the sense that something written over 100 years ago is no longer believed. It has failed in the sense that things which are obviously inconsistent with the data are being published.
#31 Joe Seydl
March 23, 2011

“That leads to another issue, which is that economics has to be viewed in part as a social science.”

This is the key takeaway. Or, even to some extent, I would argue that economics has to be viewed in part as an art.

http://joeseydl.blogspot.com/2011/03/dismal-art.html
#32 David Pearson
March 23, 2011

DeLong’s analogy to biology is ironic given that economists fail to look at the economy as an ecological system of firms and households.

In particular, the fail to see that the Fed’s actions results in homogeneity in adaptive strategies. In 2003 they signaled through “extended period” language and the “Greenspan Put” that increasing leverage and reducing liquidity insurance would be the most successful strategy. The resulting jump in shadow bank and household borrowing/illiquidity fed the recovery. Unfortunately, an ecological system with homogeneous strategies is more fragile and prone to collapse. In fact, all it took was a flattening out of home prices to bring the system down. To this day, the Fed and most economists fail to see the unintended — ecological — consequences of Fed actions.
#33 Britonomist
March 23, 2011

Okay, so Russ Roberts doesn’t understand biology, fine. That doesn’t then give you an excuse to rant about economics, when you (quite clearly) have literally no clue as to what you’re talking about. I mean really, citing obviously biased BLOG posts as evidence for what you’re saying? Get a fuckin grip. If you can’t support what you’re saying without examples from actual economic literature, then you can’t support what you’re saying – therefore, don’t say it.
#34 heteromeles
March 23, 2011

A side note/rant: Speaking as an ecologist,can we please get over physics being the gold standard of testable science? Or at least the cosmology part?

I mean, current cosmological models say that we don’t know what 96 percent of the universe is. Maybe. They think the universe is made of this stuff called “dark matter” and “dark energy” that we can’t detect (cough, ether, cough). Similarly, we have quantum mechanics and general relativity, which treat trivial things like time and gravity in conflicting ways, and we have allegedly reputable physicists saying that time doesn’t exist, because they can’t make the math work in their favorite version of string theory if they include time.

Compare this with Evolutionary Theory. Yes, we should capitalize it. Despite the fact that the physicists have been grabbing billions for massive experiments, they’ve made little real progress in 20 years. Yet if you poke one, you’re inevitably told that these little problems will be solved “real soon now.”

Evolutionary biology does not have these problems. The odd thing is that biologists still have to get over physics envy. While I don’t expect physicists (or economists) to give credit where it’s due, biologists, at least, need to get over our inferiority complex. At this point in time, biology is a very, very solid science. (end rant)
#35 Wow
March 23, 2011

“Speaking as an ecologist,can we please get over physics being the gold standard of testable science? Or at least the cosmology part?”

Cosmology is not physics, it’s a small section.

So why should a thread concerning itself about physics being the gold standard be told about cosmology not being held to be the gold standard?

“I mean, current cosmological models say that we don’t know what 96 percent of the universe is.”

I see no problem there. If you don’t know but say it, then you’re scientific. To gloss over it like economists would be unscientific.

“They think the universe is made of this stuff called “dark matter” and “dark energy” that we can’t detect (cough, ether, cough).”

See, I think you’ve got enough knowledge here to know less than nothing.

Dark matter is an explanation of its properties. It’s also nothing like aether. It’s matter, so not some sort of mystical fluid like aether and it’s dark which is why you can’t see it. Just like the horsehead nebula is a cold (therefore dark) cloud in front of a hot (therefore bright) emission nebula.

“Similarly, we have quantum mechanics and general relativity, which treat trivial things like time and gravity in conflicting ways”

This again is not unscientific. It’s proof that neither have the right idea.

Just like the engineer deals with a flat floor which in fact is a small section of a gigantic spheroid, he’s correct for a small house, wrong for the distance across the ocean.

Or PV=nRT holds until you have very rare or very dense gasses.

Or, really, all science. It defines the realms within which the idea is applicable. Heck thermometers have a range within which they are considered reference, outside which they are false.

“Evolutionary biology does not have these problems.”

So you say. Please tell me about punctuated equilibrium vs continuous change. Is that now sorted out once and for all?

“The odd thing is that biologists still have to get over physics envy”

Yes, please do so. Then you may decide not to knock down shibboleths of your own creation and actually make sense.

“biologists, at least, need to get over our inferiority complex.”

There’s nothing complex about it: biologists ARE inferior!
#36 HCG
March 23, 2011

Umm, let’s see. You read a blog post by a libertarian economist from a backwater school, and on the basis of that launch a broadside against the entire profession without bothering to examine the literature, especially the empirical literature, to see if your comments hold up. Britonomist at no. 33 got it right, although rather saltily.

As a scientist you know that the plural of anecdote is not data.

You say: “But what was disturbing was that very few economists–or at least those that interacted with the public–were saying that the combination of rapidly rising housing prices, high personal debt and stagnating wages were a disaster waiting to happen.”

Well, there were more than a few saying that, and most prominently Krugman, who interacts with the public more than any economist alive. When politicians appoint hacks, even those with advanced degrees, to positions of authority and decision making, it is not appropriate to tarnish the profession with their sins.

All this notwithstanding, many of us from within the profession have been critical of the propensity to spin complex mathematical models, especially in macroeconomics, that are either not tested at all, or not supported by evidence. When challenged by questioning the shaky assumptions underlying the models, the common reply is that “with these assumptions, I cannot say anything”. To which my reply is “what makes you think you are saying anything?”

The basic problem in Economics is that for the most part we cannot conduct experiments (with some exceptions), and that fact make the field in fact harder that biology or physics, harder in the sense of uncovering the causal mechanisms of our various realities. And that, coupled with the requirement and urgency (the tenure clock is ticking) to publish, means that hypothesis spinning is the fall back position.
#37 Peter T
March 23, 2011

I think HCG just admitted that the profession is guilty as charged – “hypothesis spinning is the fall-back position”.

There are lots of disciplines in which one cannot do experiments – paleontology, paleoclimate, history…What do these do? They take the facts seriously. And spend lots of time looking for facts to test various hypotheses. Is this the case with economics? I have not systematically tested the field, but a number of those who have have pointed out that articles in the most prestigious economics journals rarely marshall facts against some hypothesis, that most rarely marshall facts at all, and that hyptheseses that have been comprehensively discredited are still advocated by leading members of the profession.
#38 Steve L
March 24, 2011

Comparisons/contrasts among fields are useful in helping us to understand them. I think this is a useful contribution to furthering that understanding.
#39 Corporate Serf
March 24, 2011

Perhaps the real problem is that economics is used by policymakers (ie people with the real power) as a justification for whatever policies they prefer at that moment (goes for both sides of the aisle). Biology, chemistry, physics and mathematics does not face that overwhelming pressure to bend down or else.

Politicians (democrats and republicans) dont really care about niceties of predictions, tests of hypothesis, messiness, and so on.
#40 HCG
March 24, 2011

A correction of a typo: “with these assumptions, I cannot say anything”. To which my reply is “what makes you think you are saying anything?”

should be:

“WITHOUT these assumptions, I cannot say anything”. To which my reply is “what makes you think you are saying anything?”
#41 Greg Ransom
March 24, 2011

Russ Roberts mistake was basic and simple.

He mistook claims made by ecologists for what takes place in Darwinian biology.

Instead of rant and swear like a jerk, why not show Robert how to state his VALID point in terms of the science he RIGHTLY cites as analogous to the position of economics.
#42 jane hay
March 24, 2011

@ Corporate Serf #39 – try teaching biology that includes evolution or geology in public schools today and see how much pressure you get.
#43 heteromeles
March 30, 2011

@33: Actually, I was keeping it simple to bait for arrogant physicists. Thank you.

There’s a basic, obvious point here. And yes, I’m quite aware that there’s something apparently moving galaxies around, and that the universe acts as if Einstein’s cosmological constant actually exists.

But, to strip away the braggadocio:

In any field other than cosmology, when you say: “I’m sure that something’s out there, it runs everything, but we can’t detect it…the answer is: “Where’s your evidence?” and “can you account for what you are seeing with what you can detect?”

In any field other than string theory, having fewer equations than unknowns is a bad thing.

In any field other than physics, having irreconcilable differences between general relativity and quantum mechanics over the natures of gravity and time would be considered a grave defect and a sign that the field is sadly immature.

Many physicists consider physics itself different, #1, the queen of the sciences, and so forth. That’s arrogance, and it’s not worth emulating or being envious of.

Fortunately, I know many hardworking, active physicists who are more interested in making progress in the field than BSing.
#44 Wow
April 8, 2011

“In any field other than physics, having irreconcilable differences between general relativity and quantum mechanics over the natures of gravity and time would be considered a grave defect and a sign that the field is sadly immature.”

Nope.

There’s nothing between neutransmitters firing and conscious thought.

Yet biology doesn’t have a problem. Neither does psychoanalysis.

There’s nothing between transposed genetic markers and the production of feathers.

Yet there’s no problem there either.

“Many physicists consider physics itself different”

Yes, when you talk about what other people think, you’re projecting. This may be correct despite being projecting, but it is still projection.

“#1, the queen of the sciences, and so forth.”

And now we see that you have an inferiority complex too.

“Fortunately, I know many hardworking, active physicists who are more interested in making progress in the field than BSing.”

Pity you’re not among their number.
#45 dungone
March 31, 2012

But what was disturbing was that very few economists–or at least those that interacted with the public…

Correct me if I’m wrong, but if you’re a scientist, shouldn’t you be making blanket statements about another science based on what’s in their peer-reviewed journals and not based on how it’s portrayed in the mass media or the policy decisions made by governments?

I also think that the author of this OP should have taken a couple minutes to find out that the author of the other OP is part of a school of thought in economics that is considered a crank science. The big tip-off should have been the way he says that economics is not a science and that mainstream economics is deeply flawed because of its reliance on empirical observations.

The irony isn’t lost on me. This OP is making statements about all of economics based on how they’re portrayed in the media and by one guy who is clearly against the use of the scientific method to begin with. Biology wouldn’t look that much better if we treated it that way.
#46 Wow
April 3, 2012

“This OP is making statements about all of economics based on how they’re portrayed in the media”

This poster doesn’t understand what “generalisation” means.