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.

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

--Allen

"Why Do We Have The Senses That We Have?"

A common debating tactic used by creationists and ID supporters is to ask, "why do we have the senses that we have, and not some other ones"? The answer they usually provide is something like, "because that's the way the Intelligent Designer intended them to be".

The question of why we have the senses that we do is a very interesting one. As just one example, consider the sense of sight. As a type G2V yellow dwarf star, the sun gives off a relatively narrow range of electromagnetic radiation, including (from longest wavelength to shortest) radio waves, infrared radiation, “visible (red, orange, yellow, green, blue, and purple) light", and ultraviolet light. Almost all of these wavelengths of electromagnetic radiation can penetrate the Earth’s atmosphere (although the shorter wavelengths of ultraviolet light are somewhat attenuated by absorption by ozone/O3 in the upper atmosphere).

So, which wavelengths of electromagnetic radiation can we perceive? The answer depends on who you define as “we". Vertebrates have visual pigments in the cone cells of the retina that can absorb only three of these wavelengths: red (absorbed by the rhodopsin protein erythrolabe, which absorbs sunlight in the range of 564–580 nanometers), green (absorbed by the rhodopsin protein chlorolabe, which absorbs sunlight in the range of 534–545 nanometers), and blue (absorbed by the rhodopsin protein cyanolabe, which absorbs sunlight in the range of 420–440 nanometers). So, we vertebrates can only directly perceive red, green, and blue light (that’s why color computer monitors generate only red, green, and blue pixels).

However, most insects (including honey bees) have different visual pigments, and so see very different colors than we do. They do not have a visual pigment that corresponds to vertebrate erythrolabe, and so cannot perceive the color we call “red". However, they have a visual pigment vertebrates do not have, which can absorb light in the near ultraviolet range. Hence, insects can see colors (including ultraviolet) that we cannot see, and so the world appears very different to them.

So far, no organism on Earth has been discovered that can perceive the radio waves given off by the sun. This is probably because to do so would require absorptive structures several meters in length (the wavelength of most radio waves).

So, one answer to the creationist's question is that, taken as a whole, living organisms can perceive (or at least absorb) a range of light from the far infrared to the near ultraviolet, but lack receptors for most of the electromagnetic spectrum (such as radio waves, gamma radiation, etc). In other words, the range of electromagnetic radiation that can be perceived by living organisms matches quite closely the range of electromagnetic radiation given off by the sun and transmitted through the Earth’s atmosphere (with the exception of radio waves, which are too long to by absorbed by any known biological molecule).

That this is the case is exactly what one would expect to have evolved by natural selection, which can only work with what is available. Furthermore, it illustrates one of the basic ideas of evolutionary descent with modification: that the solutions to evolutionary problems vary from group to group as the result of historical contingency. Vertebrates see red, green, and blue, while insects see green, blue, and ultraviolet because two of our visual pigments (chlorolabe and cyanolabe) evolved before the divergence of insects and vertebrates from our common ancestor, while the third visual pigment evolved independently in the two groups, resulting in two different sets of perceived colors.

Compare this to the answer that ID provides: vision is the way it is because that’s how the Intelligent Designer intended it to be. Which of these answers to the creationist's query involves detailed empirical scientific investigation, and which simply relies on unsupported assertions?

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

--Allen