science

Debating Evolution Skeptics on YouTube (with a little help from Stephen Jay Gould)

Evolution untenable?

Evolution untenable?

I get a bit worked up about evolution deniers. So much so that I spend much more time than I should engaging individuals in online discussions and forums, who, for whatever reason (okay, the reason is always religions) deny evolution. Without a doubt, they get most upset when I use the word “fact” to describe evolution by natural selection.

“Isn’t that very unscientific of you, to say evolution is a fact? It is just a theory¬†after all.”

Well, yes and no. That last sentence betrays a fundamental misunderstanding of the what a scientific theory is, relative to other types of “theories”. A scientific theory is a very specific thing, it’s not the same thing as a theory about who killed Kennedy or a theory about who will win the Superbowl or even a theory about market behavior in economics. A scientific theory is an idea that has broad explanatory power, has been tested and verified by different objective observers, is consistent with other bodies of scientific knowledge, and explains particular facts. Facts, in turn, are just things that happen: e.g., apples fall when you drop them, humans evolved from apelike ancestors, the earth is an oblate spheroid. Scientific theories explain these facts – the theory of gravitation in the first (and last) instance, and Darwin’s theory of evolution in the second. It is possible these theories will be modified in the future, as Newton’s was by Einstein, but apples will still fall and humans will still have evolved from apelike ancestors – the facts don’t change.

A few individuals seem to be under the impression nothing can be proved or rightly called a “fact”. These people are playing a game with semantics. In any real sense, evolution is a fact, and descent with modification (Darwin’s preferred term) is the profoundly powerful theory that explains it.

If I could ask the American public to sit down and read one essay, it would be the late and inimitable Stephen Jay Gould’sEvolution as Fact and Theory” – he says everything I just have with much more eloquence. Go read it, and consider offering it up the next time you’re spending too much time in a debate on YouTube.

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“The universe is made of stories, not atoms” – Muriel Rukeyser

That pretty line above is from poet Muriel Rukeyser, and it’s used skillfully by physicist Sean Carroll in his keynote speech at the 2013 American Humanist Association Conference in San Diego just a few days ago. The talk is titled “Purpose and the Universe” and if you’ve never heard Carroll lecture before, I recommend sitting down for an hour and giving him a listen. He’s entertaining, likable, and has a knack for lucidly explaining concepts like quantum field theory in just a few slides.

Highlights for me included:

  • Carroll’s claim that the “laws of physics underlying the experiences of our everyday lives are completely known.” He’s of course not saying that physics is done or that there aren’t undiscovered particles or fields, but that we do know a complete regime of physics, and anything else we discover won’t have any real application to our lives. He explains exactly how we know that, and why we can rule out certain alternatives (assuming quantum field theory is correct). The completeness of this regime has obvious explanatory power, and can absolutely demolish particular claims that would require a different set of physical laws – one obvious one is astrology and another, which is equally implied by the laws but harder for many to accept, is life after death (see this blog post by Carroll for more on that).
  • Carroll’s disagreement with many of his atheist/humanist colleagues that science will be able to supply answers to questions of purpose, right and wrong, and ultimate meaning. These concepts, Carroll thinks, must be judged more practically and cannot be reduced to the laws of physics (though any answers we come up with certainly shouldn’t be incompatible with the laws of physics).
  • Learning that the underlying reality of the universe is made up not of particles but of waves and fields. The act of observation distorts the field in a certain way so that we “see” particles, though at its base nature is simply a collection of vibrating fields.
  • Special guest Richard Dawkins (who was in town to moderate a panel on “Religion as Child Abuse”) asking a question at 1:00:56 and making a slight correction to one of Carroll’s slides. How cheeky.