Note: I’m in the middle of writing a series on the history and prospects of advanced nanotechnology, prompted by the recent 50th anniversary of Feynman’s historic talk, “There’s Plenty of Room at the Bottom”. The next will discuss what the U.S. National Research Council has said about advanced molecular manufacturing, including its recommendations.
I’ve been asked some good, challenging questions, and would like to offer a reply.
In my previous post, “For Darwin’s sake, reject ‘Darwin-ism’”, I argued that the term “Darwinism” is worse than useless, and (more boldly) asked whether it makes sense — both tactically and in a deeper sense — to discuss evolutionary principles, processes, history, and so on, in terms of something called “the theory of evolution”.
Ed Regis, a professional philosopher who also writes on intelligence and science, raised important and challenging questions in a comment, and my reply grew (and grew) into the following post.
In the first section, I discuss science-“isms” and other questionable terminology, and in the second, I argue against speaking of evolution as “a theory”, comparable to quantum field theory, rather describing it as a body of knowledge that includes powerful generalizations and principles, more nearly comparable to chemistry.
@ Ed Regis — Thanks for your comments and questions (which I’ve placed in two chunks below). What I wrote was intended as a brief polemic on public rhetoric in the context of a mud-wrestling-level war on science, and I should say more about some of the points. Also, in stating my argument, I ventured into the territory of philosophy of science, and hence in to a lion’s den. My casual remark on the status of the idea of a “theory of evolution” calls, as you suggest, for some explanation.
What follows grew into a blog post, but I framed it as a reply to your comment, so the result is a somewhat of a hybrid.
Words and human contexts
Ed Regis:
Depriving ourselves of both “Darwinism” and “the theory of evolution” as essentially shorthand for the modern evolutionary synthesis leaves us with quite a vacuum in nomenclature. What term or terms do you suggest we use in its place, given that “the modern evolutionary synthesis” is quite a mouthful? (There are other perfectly good and proper -isms within science, indeed even with the theory of evolution itself: gradualism, saltationism, and punctuationsm; and, in geology, catastrophism and uniformitariansm.)
Before diving in, I should note that the appropriate use of language depends on the context, and here I see at least three:
- Professional science
- Philosophy and history of science
- Public education and debate
Your professional background highlights context (2); in the previous post, I had focused on context (3) as seen from context (1).
Re. “isms”:
Context (2) often speaks in terms of “isms” when generalizing about schools of thought and intellectual trends, and this seems fine. Indeed, in any context where a term has a technical definition, and connotations are faded or irrelevant, there can’t be much problem with a suffix on the word. Area (3), of course, isn’t one of those contexts, especially on what amounts to a battlefield. Connotations can matter a lot, and they can interfere — or be used to interfere — with efforts to transmit even technical knowledge.
In this connection, although scientists have used some of the terms you mention (gradualism, saltationism, punctuationism, catastrophism and uniformitariansm) when debating contemporary ideas, it is my impression from reading history and following debates that they have most often used these terms as labels for views that they don’t support, or actively oppose. I’m sure you recall the use of “ism” labels in poison-the-well efforts in my area.
Considering another facet of this, to the extent that scientists have adopted the positions that the labels at least suggest, they’ve ended up in untenable positions, because each “ism” suggests a rigid over-generalization.
For example, the ideas labeled “gradualism” are highlight the central role of slow processes in shaping the Earth, yet when wrapped as a dogmatic, overgeneralized “ism”, these sound ideas about some phenomena fostered a scientifically groundless, ideological opposition to recognizing others, for example, the role of asteroid impacts in extinction. Likewise, it is widely recognized that the gradualism/punctuationism debate was inappropriately polarized, and I suspect that the mutually-exclusive connotations of these ism-terms contributed substantially. Thinking is more than just words, but words do shape thought.
Re. “The theory of evolution” as a term
The term “the theory of evolution” finds more use in context (2) than in context (1), and aside from spillover into context (3), I see no problem with it. In context (3), however, I think that it is poisonous, and the more it can be avoided, the better.
Defending “the theory of evolution”— when the intent is to what we know about evolution — burdens the task of educating the public about evolution with the task of simultaneously teach those same people to understand the word as saying something that conflicts with its usual meaning, as reflected in its dictionary definitions (which include, in other than “technical use”, per Dictionary.com, “proposed explanation”, “speculation”, “conjecture”, and “guess”). To use the term “theory” to describe knowledge is, in effect, to say “You should accept as fact what scientists think might be true.” As I said before, this is self-defeating.
The term is also quite unnecessary. I don’t know of anything that needs to be said in context (3) that isn’t better phrased in terms of the process of evolution, principles of evolution, examples of evolution, causes of evolution, history of evolution, the central role of evolution in biology, and so on.
[3 Dec. update in response to a comment: I don’t expect the term to go away, particularly in discussions of the history of ideas (where the term has played a central role), and in discussions of how the major theoretical concepts in evolution have evolved. The problem is chiefly in context (3), where explaining evolution and the unfamiliar technical meaning of “theory” in science (“a more or less verified or established explanation accounting for known facts or phenomena”) adds unnecessary difficulty and makes it easier for opponents to exploit public ignorance regarding this point. As I said, the more term can be avoided, the better.]
[3 Dec. update: In response to another comment, I should note that I don’t advocate actively rejecting the term in context (3), or anywhere. To talk that way would, of course, be focusing discussion on the term again, and in a perverse and destructive way. What I advocate is a strong bias toward talking instead about evolutionary facts, principles, and so on. Language along these lines might strike the right balance: “Like the Einstein’s theories, the theory of evolution isn’t a guess, it is a well-tested framework for understanding nature, and I’d like to share with you some of what we’ve learned...” then, by preference, tell stories about nature and discovery that illustrate various aspects of evolutionary history, principles, etc.]
(I also suggest minimizing use of the term “evidence for evolution”— would one speak of “evidence for” the Earth being round, or the Earth circling the Sun, centuries of navigating Earth’s oceans, and decades of navigating the Solar System? This use of language would be jarring, because it suggests an open question with evidence on the other side. Scientists are not looking for “evidence of evolution”, and that is a revealing fact about the mature status of the science. It would be better, I think, to speak of “what scientists have discovered about”, “clear examples of”, and the like.)
“The Theory of Evolution” as a concept
[3 Dec. update, continued: Also in response to comments, I should emphasize that this section is making an academic point in the field that goes by the name of “philosophy of science” and it is relevant to context (3) debates, etc., only to the extent that it might increase comfort with the idea that a single somewhat-physics-like “theory” isn’t what it’s all about, anyway. (And my thanks to commenters for help in saying what I mean — and in better understanding what I should mean.)]
Ed Regis:
As for: “What the field doesn’t have, however, and doesn’t need, is a single, comprehensive, falsifiable theory to test or buttress with evidence. The modern evolutionary synthesis isn’t like that.”
You present no evidence for this claim, and it is not clear on the face of it that it’s true. To the extent that it is in fact a synthesis, the modern evolutionary synthesis is “a single, falsifiable to test or buttress with evidence.” It’s a theory with several component parts, an attribute it shares with several other scientific theories, including quantum field theory, string theory, and relativity theory. Those components are: the principles of common descent, random modification, and natural selection, coupled with Mendelian genetics, and the mechanisms of inheritance as embodied in DNA. Each of those component parts is itself supported by a substantial body of empirical evidence, and, therefore, so is the theory that combines them into a single comprehensive structure.
It is surely legitimate to speak of “a theory of evolution” in the traditional way, and in contexts (1) and (2), I don’t see much harm in it. Still, I think that the term is problematic unless we recognize that the term “theory” is being used to refer to two very different sorts of knowledge. [I’m sure that I should be citing someone here, and will update this to give proper credit if I find out who to give it to.]
The examples you mention for comparison, quantum field theory, [string theory*,] and relativity theory, are all universal, mathematical, precise, and physical [* is there one, in the usual sense of the word?]. Quantum field theory or general relativity could in principle be falsified, as a whole, by a single, well-substantiated observation, and don’t see in them any separable component parts that could be independently falsified by empirical evidence.
Evolutionary biology seems to me more like chemistry, geology, physiology, or astronomy. These bodies of knowledge are a fabric of facts, powerful theories, generalizations about diverse processes; they include many theoretical models, but they aren’t said to be organized around a single theory. Accordingly, this reason, they don’t stand or fall on particular observations, and are reasonably well insulated from changes in deeper theories that they (in some) sense stand on. Practical quantum chemistry, for example, is based on approximations to Schrödinger’s non-relativistic approximation to actual quantum mechanics, with relativistic corrections tacked on to describe effects that are inherent in Dirac’s theory, which isn’t directly used; the next deeper level, quantum field theory, might as well be in a different world.
There may be more standard terminology or distinctions, but I’ll call these “explanatory sciences”, because they center on observing, generalizing, and explaining their subject matter. I’ll call the more physics-like fields “exact sciences”, because they center on what are, in principle, exact measurements and on theories that make exact predictions.
The exact sciences and explanatory sciences have deep differences.
Exact sciences have theories that are intended to be universally applicable in some domain (which, for fundamental physics, is the whole universe). They say “For all (x) satisfying conditions y, the result will be z = f(x)”, where f is, of course, the theory.
Explanatory sciences, by contrast, have observations, generalizations, and among these, theories. They typically have statements of the form “There exists (x), or many xs, that satisfy conditions y, and [sometimes, or usually, or probably, or always] have (or do) z = f(x)”, where f may or may not look like a theory in the strong sense. If f doesn’t always hold, it’s routine for a scientist to narrow the conditions, or just note that there are exceptions observed with such-and-such frequency. Generalizations are useful for explanation and prediction, and generalizations with a few exceptions can be almost as useful.
The modern evolutionary synthesis fits this pattern. Its principles aren’t like those of physical law; they are generalizations with exceptions.
The list of components you offer, for example, captures the essential elements of an understanding of evolution of enormous scope and explanatory power. But as you know, these components have exceptions, often noted in more detailed descriptions. Here’s my list:
- Natural selection — Yes, but there is also change by neutral mutation and genetic drift.
- Random modification — Yes, in a crucial sense, yet mutations are more frequent at sites where they are more likely to be adaptive.
- Mendelian genetics — Often, but bacteria, among other organisms, transmit and shuffle their genes in non-Mendelian ways.
- Inheritance through DNA — Usually, but some viruses use RNA, and some cells have structures propagated simply by conservation of form during growth and division.
- Common descent — The common ancestry of all known organisms is hard to doubt, but the qualifier “known” is necessary, and finding an exception (whether on Earth or elsewhere) would be just that — another exception that would require some clarification of the scope of the statement.
It’s reasonable to call the modern synthesis a theory, provided that one recognizes its many differences from theories in physics. But now we’re considering yet another detour into explaining a meaning of “theory”, when the whole semantic muddle seems better to avoid.
On knowledge about knowledge, see:
On evolutionary themes, see:
- For Darwin’s sake, reject “Darwin-ism”
- Evolutionary Capacity: Why organisms cannot be like machines
- For Darwin Day: On the Origin of Genetic Information
- Machines Evolving to the Brink of Failure
- Homo floresiensis, Crows, and the Baldwin Effect
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Ed Regis 01.03.10 at 6:01 pm UTC
Thanks for your thoughtful and detailed post in reply to my comment. There’s nothing I disagree with in what you say about “isms” or in your further specification of the principles that constitute the modern synthesis or in your description of the differences between the exact and explanatory sciences.
[Note: I’ve edited the post in response to the points that Ed criticizes in the following paragraph, with the aim of clarifying the limited scope of my recommendations, and the reasons for them. — Eric]
I continue to disagree, however, with your attempt to rid us of “the theory of evolution” as a term. This term has such an enormous history behind it and is by now so well-entrenched in each of the three contexts you mention that I regard it as hopeless to banish it at this late stage of the game. Further, there is a way to make clear what it means even in context (3) Public education and debate. This is to distinguish at the outset between the colloquial meaning of “theory” as a guess or conjecture, and its more formal, scientific, technical meaning. This, indeed, is exactly what United States District Judge John E. Jones III did in his 2005 decision of the case Kitzmiller v. Dover School District, where he distinguished between the “colloquial or popular understanding of the term ‘theory’… [as a] a highly questionable ‘opinion’ or a ‘hunch,’” and its scientific meaning as a body of explanatory principles supported by fact. In the context of public education and debate, the next task is to lay out the principles in question and the factual evidence supporting them.
Re:
“No one is looking for ‘evidence of evolution,’ and that is a revealing fact about the mature status of the science.”
[Note: I’ve edited the post to read “Scientists are not looking for...” — Eric]
In the sense you intend it, as a statement about evolutionary theorists, this may be true (although I’m not sure about that). But in the arena of public education and debate, many people, including students and intelligent laymen, are looking for the evidence of evolution. (In fact I was doing so myself when writing a book chapter on the subject; I found a lot more evidence than I had imagined there would be.) It is the job of those people in a position to do so—teachers, science writers, and scientists themselves—to present that evidence in the clearest terms possible. It is evidence that will win this battle, not terminological revisionism. (One more “–ism,” unfortunately.)
Eric Drexler 01.03.10 at 10:19 pm UTC
Ed — Thanks for your further comments; I’ve edited the post in response, embedding notes in your comment so that readers won’t be puzzled by how it relates to the revised content of the post.
I’ve inserted a paragraph to clarify the limited scope of my recommendations and expectations re. “the theory of evolution”: the term is necessary in discussing the history of ideas, and can’t be expected to disappear from public discourse. I also emphasize the unnecessary difficulty of what is, as you say, surely possible — that is, to explain scientific knowledge of evolution despite labeling that knowledge with a term that means, in common use, the opposite of knowledge. I just think that it’s best to avoid the problem.
I’ve also revised a sentence to more clearly state what you correctly read as a reference to scientists’ (not the public’s) lack of interest in finding “evidence for evolution”. I do think that that vivid and compelling evidence be presented to the public, but as “information about” rather than “evidence for”. This better reflects the status of knowledge and inquiry in the area. There’s ample evidence for the existence of China today, and Rome in the past, but it would seem silly to call it that.
Note that people who speak of “evidence for the Holocaust” are either deniers, or (I would argue) have been lured into playing their game. The deniers should be answered, perhaps by mentioning the essential facts as part of a broader story of historical genocide before, during, and after the slaughter of Jews and millions others, including Gypsies and Soviet prisoners of war (Holocaust Museum Encyclopedia). The story is stronger than any part, and the parts share the strength of the story. To use the deniers’ term, “evidence”, though, would be to frame the historical fact as questionable. Likewise with evolution.
[In response to the comment below, I should note that the preceding example came to mind as a familiar and vivid (on reflection, perhaps too vivid) illustration of a parallel between patterns of language in argumentation, and only that: a comparison of words, not of their speakers. The moral and political dimensions of the content of the arguments are of course not remotely comparable.]
Unidentified 01.04.10 at 2:24 am UTC
I’ve been thinking a lot about terminology (in a different context), and I like your “punctuationism / gradualism” example in a more general sense, as a scenario where the erroneous effects of sloppy language on thought, and thusly on the speakers’ concept of the world itself, are (relatively) readily apparent. I’m going to mentally benchmark that as a “why linguistic inertia is not sufficient justification for preserving terminology in a way supports overreaching or erroneous implications” argument.
On another note, I think it’s disingenuous to insinuate that the logic of principles in evolution is inconsistent with that of physical principles or that physics is an “exact science” in opposition to an “explanatory science.” Physical laws do not describe the body of our understanding of “physics”, physical theories do, and physical theories are both explanatory and generalized. Evolutionary science may be distinct in that the closest equivalent of a “law” is simply the fact that evolution happens, but the word “theory” has the same logical meaning whether you’re talking physics or evolution.
I also disagree with removing the phrase “Theory of Evolution” from the public discourse for a couple main reasons.
- Reactionary: “Theory” will continue to be used by denialists no matter how thorough an attempt is made by scientific advocates to “clean up” their own language. In this case, we are left in the dubious-looking position of discouraging the use of the term while being unable to actually make the argument that it is logically incorrect to use. The message this makes? “The theoretical status of evolution is an inconvenient fact for the evolutionists! You’re trying to censor it away!”
The reason you’re here making these points in the first place is that there is a manufactured “controversy” and it has two sides, one of which is diametrically opposed to you. It is necessary to consider their potential response.
-Educational: I fundamentally disagree with your separation of the “technical” and the “public/educational” on this issue. The solution is not to simply ignore the technical definition–if anything, what this is (and what it has been used for, in my experience) is a learning point on the use of “theory” in a scientific context. That’s a good thing! We don’t, say, need kids to encounter “the theory of special relativity” and assume that that means it must be dubious. “Theory” is going to pop up eventually when it comes to learning about science, it’s best that its use be understood.
Understanding the usage of “theory” is an important part of understanding scientific reasoning, which I hope we can agree is a powerful thing. I support more opportunities to make its meaning less opaque to the general public and, terrible as the existence of “controversy” around evolution in this country is, it provides a talking point for that.
“I don’t expect the term to go away, particularly in discussions of the history of ideas (where the term has played a central role), and in discussions of how the major theoretical concepts in evolution have evolved. “
“Theory” is not a historical term, it’s a current term. The theoretical status of evolution, as an association and explanation of phenomena, is not “historic” in the sense of being “a thing of the past.” “It was a theory, but it was right so it changed!” is a toxic misconception.
I’m going to tentatively agree with your statements about the use of the word “evidence” (which makes me cringe) with exception to the use of the holocaust as a point of reference, which I feel is disingenuous and offensive. I’d point to gravity instead: we know things fall. No one is sitting around letting things go and calling it “evidence.”
Eric Drexler 01.04.10 at 9:54 am UTC
@ Unidentified —
Thanks for your thoughtful and valuable comments. I agree with several of your points, and I’ve revised the post to clarify what I intended to say, or perhaps, what I should have intended to say. In particular, I note that actively rejecting the term “theory of evolution” would be neither well-motivated intellectually, nor wise tactically, nor consistent with what I’ve suggested. I think you make the reasons for this very clear.
Re. education, yes, to the extent that the context is educational rather than confrontational, explaining the meaning of “theory” in science is valuable — not so much as a direct aid to anyone’s understanding of evolution, but as a contribution to their general knowledge of science.
Re. my closing example of other denial rhetoric and responses to it, thank you for pointing out the noxious way in which it could be read. I removed an avoidable hot-button word and appended a comment to clarify that I intended “a comparison of words, not of their speakers” and that the instances are in other respects not remotely similar.
Re. whether “the word ‘theory’ has the same logical meaning whether you’re talking physics or evolution” — I don’t object to (what I argue is) stretching the term “theory” to cover both, but I do see them as quite different at what is very much a logical level:
A universal physical theory that asserts “For all…” has a logical status fundamentally different from that of a biological theory that asserts “There exists…”, even if the assertion is “There exists an overwhelming prevalence of [some physical or causal pattern], and it seems to be universal for all life on Earth”. The first is falsifiable in a strong sense, eternally, because one can never examine “all”. A simple “There exists x” statement by contrast, is verifiable (“There exists x, and here’s a picture of x, and a sample of its hair”) but not falsifiable, provided that exhaustive observations are impossible. There’s muddy ground in this area, because a biologist can certainly assert falsifiable universals; I just don’t see them as central or necessary to the field.
Instead, I see the theoretical understanding of evolution as consisting of strong generalizations that describe what has been observed, or reasonably inferred, to exist, or to have happened, and the underlying causal mechanisms. I don’t see biologists as very concerned about the possibility that there may somewhere be things or phenomena that work in a way that their generalizations don’t cover (except as an opportunity for discovery that would add to, not overthrow, the present understanding). Physicists, by contrast, are intensely interested in just that, because their generalizations are of a kind that could be decisively overthrown by a phenomenon 13 billion years and light years distant.
(BTW, I take your point about the different nature of more mundane, less fundamental physics; lofty philosophical debates about The Nature of Scientific Theory very often neglect the patchwork and globally robust nature of most scientific knowledge.)
Re. Historical vs. current uses, yes, it’s a current term, and what I meant to say is that using it is absolutely unavoidable in discussing the history of ideas, since it is an integral part of that history. In the present, my view is that it is, at the moment, an integral part of discussions, at least, and that it is of-course-OK-to-use-but-unnecessary-and-good-to-deemphasize-but-wrong-to-reject (is there a word for that?).
Chris Phoenix 01.04.10 at 9:08 pm UTC
Those who want to believe that God created the species really don’t care much about most of the field of evolution. DNA, inheritance, and so on are assuredly part of the scientific field of evolution, but have little to do with the question of whether species came from God or from natural processes unaided by miracles.
When discussing evolution with a creationist, it’s important to keep in mind several points:
1) They focus on the source of species. Any examples that shake up their concept of species are useful. For example, seagull species form an inter-breeding continuum around the world – but where the ends of the continuum overlap, the endpoints don’t interbreed. It may also be useful to talk about crossings between plant species and even genera, which are quite common – more so than in animals.
2) They probably have not thought much about the fact that their belief requires literal miracles. A useful approach is, “Science studies how things might work in the absence of miracles. If we can find a mechanism or process that does not require miracles, then it’s up to each person’s faith to decide whether miracles were involved anyway. But miracles are not within the purview of science.” It may take some time before they will even acknowledge that creationism requires miracles.
3) They know they are right. They may be trying to convert you, either to a belief in God’s creative acts, or (perhaps more likely these days) to a belief that the educational system is inappropriately teaching evolutionism. They may actually understand evolution reasonably well, but reject it nonetheless. Their reasons for rejection may be based on detailed argument, simple misinformation, rhetoric, or any combination of the above; in any case, reasoned argument with their statements will probably be inefficient.
4) With most creationists, this is more a matter of politics and/or faith than of science. Unless you can shake up their basic worldview (as by undermining the concept of species), or recast the discussion (for example, by defining miracles out of science), you will not get anywhere by talking scientifically.
5) They may have legitimate grievances against science. There’s a continuum between “Science studies how things would work without miracles” and “Scientists’ job is to convince people that the world is godless.” Scientists are scattered across this continuum. Thus, creationists have heard scientists tell their children that God does not exist… and they see evolution as a way to get anti-God propaganda into the schools. There are all sorts of subtleties here, and no obvious easy right answer.
Chris
Arv Edgeworth 01.05.10 at 12:08 am UTC
You speak of creationism as a worldview, and don’t like the term “theory of evolution,” but aren’t they both really just worldviews? Isn’t science supposed to be neutral towards the supernatural? If one does not believe in the supernatural, isn’t that a form of scientific naturalism, which is a worldview?
I understand only interpreting natural phenomena in terms of natural processes, but who determines what is natural or supernatural? What if the beginning of the universe and of life were not natural phenomena, but were supernatural in nature? Should scientists try to explain supernatural phenomena in natural terms?
If scientific evidence would seem to indicate design or purpose for example, or perhaps that it could not have had a natural cause, if science were truly neutral in regards to the supernatural, should this type of dialog be censored from the classroom?
Eric Drexler 01.07.10 at 11:30 am UTC
@ Chris Phoenix — You make good points; I’d just like to note that there’s a question of context to keep in mind, and that is the intended audience, which varies with the situation.
I tend to think in terms of a public forum in which the audience represents a spectrum of views. In polarized public debates, there’s a temptation to think of those making the argument on the other side as the audience, and when replying to them, to think in terms of persuading them. This may be hopeless — they’re the other pole — and isn’t usually the best objective. It’s better to think in terms of swaying the uncommitted.
I recall in the political blogosphere reading laments about how those people on the other side were hopeless — because the lamenter paid attention to the most visible people, which is to say, the most noisy and extreme and unreachable. Eric Hoffer had something to say about this.
Eric Drexler 01.07.10 at 11:51 am UTC
@ Arv Edgeworth — In my view, the natural world is a network of cause and effect, and if something is linked to the natural world by cause and effect, then it is part of the natural world. All manner of strange and invisible forces and influences have pressed their way into scientific understanding, from gravity to germs, radio waves, and neutrinos. Each was outside some previous framework of the human understanding of nature, but that didn’t make it supernatural.