Sunday, August 02, 2015

Defending Evolution

One of the things I find utterly appalling is the number of people in the US that reject the Theory of Evolution.

Every once in a while I will make the mistake of responding to a video or opinion piece which purports to "disprove" Evolution and I will get into an extended exchange of posts with someone of that ilk. I used to do this more often when I was naive enough to still think that evidence mattered.

I know it's a waste of time but I get sucked in until I finally throw my hands up and exit the conversation.

It's unbelievable, it really is, how misinformed people are about science in general and evolution in particular. I suspect one reason for this is that in many areas of the country the topic is so fraught with peril that the schools gloss over it.

It's also incredible about the things they "know" to be true that are just flat out wrong. You run into the same objections over and over again. That groaning sound you hear is me being told for the umpteenth time that "there are no Transitional Fossils" or "Radiometric Dating doesn't work" or "the 2nd Law of Thermodynamics disproves Evolution" or "a cat can't give birth to a dog" or simply "that (whatever evidence it may have been) still doesn't prove Evolution."

Yes there are Transitional Fossils. Hundreds of them in fact but one has to understand what constitutes a Transitional Fossil. It is not a creature that's half of one species and half of another. It's a fossil that has the traits of different types of animals. For instance a fish with feet (Tiktaalik) or a reptile with the features of a bird (Archaeopteryx) to name two of the more famous.

Yes Radiometric Dating works. There are between 35 and 40 methods and they all agree within 3%-5% of each other. This validates the one critical assumption that radioactive decay occurs at a constant rate per isotope. The common objections such as the unknown starting quantities and possible contamination can be eliminated by using the slightly more complicated Isochron Dating method.

No the 2nd Law of Thermodynamics doesn't disprove Evolution because the Earth's Biosphere is not a closed system. It is constantly importing energy from the sun. If that weren't the case a seed couldn't grow into a plant; a fetus couldn't develop into a baby and a baby couldn't mature into an adult.

It's a true statement that a cat can't give birth to a dog and Evolution doesn't say it can. As a matter of fact if a cat ever gave birth to a dog the entire fabric of Evolution would unravel because the theory says that can't happen. But, based upon the differences in DNA, cats and dogs had a common ancestor about 55 millions years ago that was not a cat or a dog.

As for "proving Evolution," technically you can't PROVE anything outside of the realm of mathematics. The Natural Sciences work with probability. What one can do is pile up evidence so high that it would be irrational not to accept something as true.

And so on and so forth. I'm not a biologist but I've educated myself adequately to understand what Evolution actually claims and why the evidence is so strong.

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