Thursday, December 09, 2010

Is Science True?

In my experience, everyone bases their "arguments on certain metaphysical suppositions, scientists and non-scientists included. As a good friend and student of E. A. Burtt, I have found his Metaphysical Foundations of Modern Physical Science to be extraordinarily useful in this regard. In fact, I have begun work on what I hope will be a companion volume: Metaphysical Foundations of Modern Biological Science, in which I will examine the assumptions that underlie the science of biology as it is practiced today.

One of the bedrock assumptions underlying both modern physics and modern biology is non-teleology: the assumption that natural processes do not include any teleological input. I personally think that this is wrong, and base my objection to this idea on Ernst Mayr's monumental book, Toward a New Philosophy of Biology, published in 1988. Mayr argued very persuasively that teleological explanations are entirely appropriate in biology insofar as they refer to the development and maintenance of living organisms. According to Mayr, both of these processes (and indeed all biological processes) are directed by programs (i.e. genomes, etc.) that pre-exist the entities and processes that they specify and regulate. In the jargon of the current debate, genomes and other developmental programs are "designs" for the assembly and operation of living organisms.

However, Mayr also argued very strongly that the origin of biological programs – that is, the various mechanisms of biological evolution – need not (and apparently do not) include any teleological component. Like all physical processes, there is no detectable "grand design" (much less a Grand Designer) which/Who has formulated beforehand the programs that regulate life. In other words, teleology is entirely appropriate when applied to life and the operation of living programs, but not when applied to the origin of life or the origin of living programs.

So, what does this say about the question of whose opinions to trust when considering these issues? My first criterion is skepticism: if someone claims to know the truth about anything at all (including, of course, the contents of their own mind), my immediate reaction is intense skepticism. Science (at least that version of it that has been practiced since the 17th century) isn't about truth. It's about reasonable confidence in explanatory models, all of which are grounded on a metaphysical assumption of the usefulness of methodological naturalism. Notice I wrote "usefulness", not "truth", because as far as I can tell the only "truth" that exists on either side of the evolution/ID divide is a version of Colbert's "truthiness". It feels like "truth", but isn't really. In my opinion, "experts" are people who keep these distinctions in mind at all times, and do not easily (if ever) use absolute statements when talking about nature.

For example, I have an immediate, knee-jerk negative reaction to the title of Jerry Coyne's book, Why Evolution is True, and indeed to much of what he writes for the general public. Consider a similar title, Why Quantum Mechanics is True, or if you prefer Why the Gas Laws are True. How would a physicist react to titles such as these? I hope (and my general experience has been) that they would object to the word "true", and also perhaps to the question "why". Physics isn't about "truth" and doesn't usually ask about "why" things happen. Physics is about "useful" and "consistent" and "empirically testable" models of reality, and it's about "how" things happen, not "why" they happen.

Indeed, in the natural sciences (including biology) the answer to the question "how" is the same as the answer to the question "why". How do birds come to have wings? They inherit a genetic and developmental program that, via interactions with their environment, produces those structures we call "wings". Why do birds come to have wings? Same answer. How have birds acquired these genetic and developmental programs? They evolved by natural selection and other evolutionary mechanisms. Why have birds acquired these genetic and developmental programs? Again, same answer.

Speculating as to whether the biological processes by which the programs that specify and regulate living organisms and processes are somehow externally/supernaturally directed seems to me to be metaphysical arguments, rather than scientific ones. Interesting, compelling even, but not part of science, at least as it has been practiced for a very long time.


As always, comments, criticisms, and suggestions are warmly welcomed!


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Saturday, December 04, 2010

Many Metabolisms, Many Origins?

An unspoken but widely held belief among both evolutionary biologists (and some "intelligent design" supporters) is the idea that life (or, to be more specific, living organisms and/or metabolic processes) originated once a very long time ago. Along with my fellow biology majors, I was taught this by William T. Keeton in introductory biology at Cornell, where we also were told that if life (or biomolecules) somehow spontaneously started again today, it would immediately be scarfed up by already living organisms.

This idea ultimately derives from the last paragraph of Darwin's Origin of Species, in which he proposed that
"There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved." [Origin of Species, 1st edition, 1859]
Darwin asserted this partly to contrast his theory of evolution from that of Lamarck's, which included the idea that life was continuously arising spontaneously, generating new phylogenetic lines of organisms throughout deep evolutionary time. The discovery of the (almost) "universal" genetic code in the 1950s by Crick, Nirenberg, Holley, Khorana, et al provided strong evidence for the "one origin" hypothesis.

However, the fact that there is currently no evidence for an alternative "many origins" hypothesis doesn't necessarily support the conclusion that this hypothesis has been falsified. On the contrary, as the recent discovery by Felisa Wolfe-Simon of a "shadow arsenic metabolism" indicates, this lack of evidence is the result of lack of investigation, rather than actual lack of such origins. It is, in other words, quite possible that life (or at least biochemical processes similar to metabolic processes and molecules similar to "standard" biomolecules, and even cell-like structures incorporating both) is "originating" spontaneously all the time, but that we haven't noticed it because we haven't been looking. After all, nobody suspected the existence of an entire domain of living organisms (i.e. the Archaea) until Carl Woese starting looking two decades ago.

As J. B. S. Haldane — who formulated an early hypothesis for the origin of life — once quipped,
"[T]he Universe is not only queerer than we suppose, but queerer than we can suppose." [Haldane, J. B. S. (1927) Possible Worlds and Other Papers, page 227]

As always, comments, criticisms, and suggestions are warmly welcomed!


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