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Nathan Lents Doesn’t Understand…Refrigeration

Nathan Lents

Darwinist Nathan Lents makes some bizarre arguments in an effort to salvage his claim that external testicles are a biological mistake. 


I raise the real cost that external testes brings to men. 

They’re certainly proving rather costly to Lents’s credibility. 

The “reason” why testes are external in most (but not all!) mammals is that sperm development (and storage, as Dr. Egnor points out) is optimal at a slightly lower temperature than our balmy 37°C body temperature. I think this is covered in 6th grade biology, so kudos to Dr. Egnor for remembering that.

Gee… why would storage work better at lower temperatures? Lents is stumped. Maybe it’s entropy. Things last longer at lower temperature. This confuses Lents. 

When a Darwinist is stumped, the first thing he does is take a swipe at the guy who stumped him:

Although Egnor is a physician, he’s not a biologist and MDs don’t actually learn much fundamental biology in medical school. I know this because I did both my graduate and postgraduate work at medical centers and was taught by a lot of the same faculty that MDs are. But here’s his biology lesson for the day…

It would seem that sharing faculty (and courses) at medical centers would be an argument that PhDs and MDs learn quite a bit of the same stuff. MDs do some pretty good basic biology. Doctors work with human biology in an intense and consequential way every day. Two of my professors in med school (Eric Kandel and Richard Axel) won Nobel Prizes. Both are MDs, not PhDs. In fact, to get into medical school, pre-med students have to be at the top of their science classes. That means outperforming most of their classmates, including guys like Lents. 

Here’s Lents synopsis of his own research:

My research lab currently has two active projects. First, we are studying the human microbiome, the community of bacteria and other microbes that live in and on us, and how this community changes following the death of the human host. The goal of this project is to develop tools to better estimate the postmortem interval (time since death) to aid death investigations. Second, we are exploring the genetic diversity in common household plants. The goal is to develop a DNA barcording system for the identification of trace plant residue recovered from crime scenes.

Lents studies rotting corpses and household plants. He might not know much about (living) human physiology, but you’d think he wouldn’t be so perplexed by the advantages of refrigeration.

Lents shows us some of the deep insights he gleaned from his graduate evolutionary biology courses:

The “optimal temperature” of any biological process is not set in stone as some fixed property. 35-36°C is  the optimal temperature for sperm development because sperm development has evolved at that temperature. The enzymes and other components have evolved structures that are most functional at that temperature.

Lents writes: “35-36°C is  the optimal temperature for sperm development because sperm development has evolved at that temperature.” The logic is: “X is optimal for Y because Y evolved at X.” Darwinian science never rests. 

Consider exothermic animals (previously called cold-blooded). Because they don’t have a steady body temperature, most of their enzymatic processes are more robust than ours so that they can tolerate the wide temperature swings throughout the day and throughout the year. Even more to the point, we find that the “optimal temperature” for things like sperm development is highly variable among those animals. Those that live in colder climates exhibit different “optimal temperatures” than those that live in warmer ones. It’s not a fixed property. That’s how natural selection works — in response to environmental pressures, species adapt, if they can.

I tried pasting this paragraph into Google Translate, from Darwinian to English. It froze. 

In case you didn’t get his point, Lents adds:

Also emphasizing this point is that plenty of warm-blooded animals have abdominal testicles also, for example sloths, elephants, and most marsupials. They do just fine. The optimal temperature for sperm production is right where it should be because sperm production has been optimized for that temperature by natural selection. This is basic biology.

“X is optimal for Y because Y evolved at X.” Where would we be without evolutionary biology?

Of course, if one applied Lents’s reasoning to biological mistakes, we would have to modify his deep Darwinian insight: “X is optimal for Y because Y evolved at X, unless it’s a mistake.”


That just happened to be the solution that evolution came up with, instead of tweaking the enzymes of sperm development to make them work well at the abdominal temperature. 

Why is it that Darwinists are unable to talk about natural selection without at some point assigning agency and purpose to it? Try as they may, they can’t even talk about biology without invoking design.  

It was just a fluke and the point of this whole discussion is that evolution is aimless, random, and clumsy.

Evolution is “aimless, random, and clumsy”? Any biologist who thinks the process that produced the genetic code, DNA replication, asexual and sexual reproduction, energy metabolism, protein synthesis, cellular biochemistry, human physiology, the heart, the eye, and the brain is “aimless, random, and clumsy” needs to spend less time with rotting corpses and more time with living biology. 

The irony here is that Lents is making design arguments all over the place, got called on it, and is trying to cover his tracks with Darwinian gibberish. Lost in Lents’s Darwinian morass is the obvious reason that human sperm are produced and stored below body temperature: to lower their metabolism and preserve them, until they are needed.

Why would Lents consider that bad design? That’s very nice design, if you ask me. And why would Lents dismiss intelligent design, when his entire argument about “poor” design depends on the design inference? 

Photo credit: Raymond Shobe, via Flickr.