Beneficial Versus Constructive Mutations

Evolutionists often interpret any beneficial mutation as evidence that Darwinism is true. After all, aren’t beneficial mutations all that is required for Darwinian evolution to occur? So long as there are occasional beneficial mutations (and a process like natural selection to favor and preserve them), couldn’t those beneficial mutations slowly add up over very long periods of time to produce the varieties of organisms we see today? The underlying assumption here (and it is a flawed one) is that if a mutation is beneficial, it must be constructive. If an organism is helped by a mutation, it must be that the organism was given something new. But, as we will see, mutations (when they help at all) typically help the organism by breaking something rather than building. One must make a careful distinction between beneficial mutations and developmental or constructive mutations. They are not the same thing, and that matters immensely in this discussion.

Boundaries and directions

Proponents of Darwinian evolution often point to observable changes in life forms, such as antibiotic-resistant bacteria or cavefish that no longer grow eyes, as evidence for evolutionary theory. One common answer (and it is a truthful one) is to point out that these are all examples of microevolution, not macroevolution. In other words, they are the kind of small variations within a particular kind of organism that everyone already agrees do occur. They don’t constitute (nor are they evidence of) anything like the sort of large-scale change from one type of creature to another that Darwinian theory demands. That is a legitimate point and can be a helpful clarification. Darwin’s critics do not deny all change. They merely point out that there are fundamental limits to the kinds of change that blind, natural forces can produce. The mechanisms of genetic mutation and natural selection exist and do provide certain adaptive benefits in a changing environment, but they can only go so far.

Yet, the “how far” question is only part of the picture. It is also important to recognize that, just because a mutation is beneficial doesn’t mean that it is adding new information or building toward a novel structure. Though contrary to our surface-level assumptions, the fact is that benefits often come from breaking or ditching existing systems or structures rather than trying to build new and more complicated ones. Thus, rather than developing or constructing a new and more complicated form of life, beneficial mutations are often simplifying and streamlining an existing form. Not only can random mutation and natural selection only go so far, they also inevitably tend to go in the wrong direction to be of any help in a grand Darwinian scheme. They move toward the helpful loss of information rather than the invention of new information.

A few analogies for beneficial mutations that are not constructive

Imagine you are in a car in the middle of nowhere and you are getting low on gas. You do the math, and you just don’t have enough fuel to get you even within walking distance of the next town. If you just keep driving, you will end up lost and stranded and likely will not survive. But if you can find a way for the car to get you just a little further, you will be able to get just close enough to be able to hike to the next town and get help. What do you do?

Well, you could try to invent a new, more fuel-efficient engine for your car. But that requires parts you do not currently have. Even if you somehow got some new parts, you don’t immediately know how to use them. You could only blindly attach them here or there by trial and error in hopes that it made a more fuel-efficient system (all the while you are losing fuel with every test drive, not to mention your growing need of food and water). This option would likely never work even if you were immortal and could keep trying it forever. It certainly would not work in time to help you. A constructive of option is not realistic.

But there is a simpler and more obvious option. You lighten the car by ditching everything that isn’t essential. Dump your luggage and spare tire. Drain unnecessary liquids like your wiper fluid. Heck, if you can remove any of them easily enough, ditch the seats, the doors, and the air-conditioning system. Knock out the windshield, windows, and mirrors. Make the thing as absolutely light as possible, and then drive at a slow, fuel-efficient speed. The mileage you will gain by breaking and discarding things you don’t need will allow your car to get much further than you could reasonably expect to go by building a complicated new system to solve the problem. This is a “beneficial mutation” of your car. It is a change that helps you. Now, sure, in the future, it would be nice to still have many of those things you ditched, but in that moment you are not planning for the future. You’re just trying to survive right now (similar to blind processes like random mutation and natural selection, which literally cannot think about or plan for the future and can only act on what is most useful at this exact moment in this exact environment.)

This is the same principle behind why desperate sailors faced with a storm may ditch cargo to lighten the ship and keep it afloat. Once they reach the port, they will certainly wish they had the cargo, but in the environment of the storm, they lacked the luxury of thinking about the future environment of the port. They did what they had to in order to survive. (Natural selection acting on random mutation lacks not only the luxury but also the ability to think about what an organism might need in a future environment.) Thus, in an unplanned emergency, a destructive but beneficial mutation is often the best option. Breaking or getting rid of things can actually help!

Or consider competitive cyclists who shave off body hair to reduce drag and resistance, giving themself a slight but measurable edge.1 If you are in an environment where speed is all that matters, getting rid of existing parts that weigh you down or make you less aerodynamic is your quickest option to gain an edge. Trying to build a whole new complex system of propulsion only helps you once it is complete and functional. In the meantime, any new structure will only weigh you down and get in the way of your outrunning predators and/or competitors. Discarding existing structures is a fast, beneficial, easy, and effective way to get ahead. A cyclist born without the ability to grow hair on their limbs would have a natural advantage in the cycling environment. This would be a beneficial mutation even though it is a loss of function. Again, beneficial is often not constructive.

When you are planning ahead, consciously preparing to face any number of possible future environments, a generalized tool is best. I used to spend a lot of time hiking and camping alone in the woods, mountains, and high deserts of Utah and hunting on the Wyoming plains. You can only carry so many things, so I put a lot of thought into decisions like what knife I should have. Because I might end up in all kinds of very different ordinary or emergency situations, I needed a blade that was able to perform a wide variety of tasks. It needed to be able to slice game and also chop, saw, or carve/whittle wood. Still more, the blade needed to be strong and durable enough to use as a prying tool, and the right metal for me to strike it with a flint rock and get sparks to make a fire. Of course, it didn’t necessarily excel at any of these tasks. It can’t slice like a razor blade. chop like an axe, or saw like, well, a saw. But in a crunch, in can do all of these tasks well enough. When you are planning ahead, you are not only concerned with what you need right now, but also what you might need in various possible futures. You sacrifice present utility for future usefulness

If, however, you can’t plan and lack all foresight; if all you can do is select for current challenges, you will get rid of functions and features that you don’t immediately need in favor of excelling at what helps you right now. To stay with our knife example, if you are in a situation that demands only slicing, you are going to make your knife sharper and sharper. You do that not by adding a new structure but simply by removing some of the metal, shaving it down to a razor edge. This makes the blade too weak to chop or pry, but that doesn’t factor in. You’re in a slicing environment right now, and so the best slicer wins the natural selection game. It’s not a constructive change, but it is a very helpful one! If, on the other hand, all you need is sawing, you will make the whole cutting edge serrated. Again, this is a deformation of the existing blade. You’re removing some of the metal to make the notches. In doing so, you become a great sawer and excel in your current environment above the competition, even if that means you are no longer fit to slice or whittle. When you can’t plan ahead, you quickly specialize to your current situation, and you do so by discarding unneeded functions, materials, information, etc. Deformation, deletion, or damage to an existing structure can have tremendous adaptive benefits, at least in the short run. and the short run is all that natural selection acting on random mutation is able to consider.

But is this really how beneficial mutations work?

Okay, so we can see that there are plenty of human situations where breaking and discarding existing systems or structures is a quick way to get ahead. Very often a destructive solution is better than constructive one. But is that really how beneficial mutations work in biology? The simple answer is, “yes!” While most mutations are just harmful and quickly die out, beneficial mutations certainly do occur. But, just like in our human examples of unplanned reactions to environments, these beneficial mutations normally break rather than build.

To take an example from our own living experience. I love eating dairy. Cheese, butter, and milk in my cereal are all practically daily staples, and ice cream is my go-to dessert. Yet my ability to digest and enjoy these foods is actually the result of a beneficial but destructive mutation.

“Lactose is a sugar that occurs naturally in milk and most dairy products. Lactose is readily broken down in the gut by an enzyme called lactase. Babies produce large amounts of lactase until they are weaned. After about 5 years of age, most people (about 75% of the world’s population) stop producing the lactase enzyme. Without lactase, they can no longer digest milk, and they become lactose intolerant.”2

Lactose intolerance in adult humans is actually the norm. The production of lactase is meant to allow an infant to nurse on his or her mother’s milk. Once one shifts to solid foods, it’s not only unhelpful but, if anything, a waste of resources to keep making an enzyme for milk consumption. That is, unless you have found an alternative source of milk. As paleoanthropologist Dr. Daniel Lieberman explains:

“after people domesticated mammals like goats and cows that supply milk, the ability to digest lactose after infancy became an advantage, promoting selection for genes that permit lactase production in adults. In fact, several such mutations evolved independently among East Africans, northern Indians, Arabs, and inhabitants of Southwest Asia and Europe.”3

Many Darwinists celebrate this as an example of their theory at work. Smithsonian Magazine proclaims, “Anyone who enjoys ice cream can thank evolution.”4 But is this really true? Sure, we’re obviously looking at beneficial mutations here, but are they constructive? Did any of these lactase mutations develop something new? No. In fact, they all remove or deform something that was already there. In each case, the mutations involve breaking the existing gene that is supposed to turn lactase production off. They cause an existing system that is supposed to turn off after weening to instead remain on indefinitely. Indeed, this is why more than one version of this effect showed up in different places. There are few ways to correctly build a thing, but there are countless ways to break it! These are beneficial mutations. They do help us, at least in an environment where dairy animals are present. But this is not the kind of constructive mutation that Darwinists need to find to demonstrate their theory.

The same goes for countless other examples. Eyeless cave fish, legless lizards, and wingless flies are all adaptation by subtraction. They involve beneficial mutations in their given environments, but these mutations are all breaking or deleting existing structures. Even popular examples like antibiotic-resistant bacteria which are often heralded as “proof” of Darwinian evolution and a “refutation” of creationism actually involve a variety of mutations that break existing systems rather than building new ones.5 These mutations are not constructive. They aren’t adding new functional information or building new systems or body plans. They are not moving in the right direction to accomplish Darwinian macroevolution. Enough of them can indeed cause noteworthy change in an organism, but that change involves a loss or at best a reordering of existing information and systems. As Dr. A.E. Wilder pointed out:

“Regrouping of genetic information may produce a new species without raising the overall amount of genetic information involved in making up such a species.”6

And we must remember that, even here, the different “species” will be a different variety of the same basic kind of creature. A fox and a wolf are distinctly different species and cannot reproduce with one another, but they are both quite obviously dogs. None of this represents the kind of development of new, complex information that must be acquired for Darwinism to work.

Beneficial mutations that are not constructive are a problem for Darwin

We must emphasize here again that all these examples are not exceptional; they are the norm. They are exactly the kind of quick, simple, and effective solution that random mutation is able to produce and natural selection will always favor. As Dr. Michael Behe points out:

“Degradative but adaptive…mutations appear quickly even on short time scales, even in small populations. They don’t need large numbers or long times to occur. Thus they will always be present everywhere in life much more quickly and in far greater numbers than constructive…mutations. Damaging yet beneficial mutations will rapidly be selected when nothing else is available and compete fiercely with any [constructive] mutations that might eventually arrive on the scene.”7

Thus, damaging but beneficial mutations are common, easy to observe, are quickly succeed, passing on to future generations. This is a serious problem for Darwinism. Any rare constructive mutation that might happen to occur would have to:

Provide an immediate benefit to survival and reproduction
Provide a sufficiently effective benefit to compete with its beneficial-but-destructive rivals
Avoid being broken or deleted itself by all of the innumerable destructive but beneficial mutations that will repeatedly follow

This is an almost insurmountable demand, and yet it’s not enough for just one such rare mutation to meet this standard. Another must just happen to build on it usefully while itself meeting that same standard. And another. And another. Over and over again, without any step in the process failing to measure up. And this is just to build even one single, simple new system. On any Darwinian model, the number and complexity of all the countless new systems that formed to produce ever variety of organism that has every lived from a single proto-bacterium are almost incomprehensible. And Darwinism needs random mutation and natural selection to be the drivers of this, but they are working against it! Random mutation is constantly producing benefits that delete information and break systems, and natural selection is always favoring and passing on these damaging (but presently beneficial) mutations, simplifying and streamlining for current circumstances without the slightest regard for the future. This process of frequent deleterious-but-helpful mutation allows organisms to rapidly adapt to new environments, but also significantly limits how far those changes can go. As Behe notes:

“Darwinian evolution is self-limiting – the same factors that make it work well on a small scale ensure that it doesn’t go very far”8

What’s more, while some systems that “turn off” can later be “turned back on” so to speak (not building something new, but resuming the original function of something that was already there), in many cases, information is lost that cannot be restored. As Behe again notes:

“Burning down a gene or control region to help adapt to one demand means it is unavailable to help adapt to future ones.”9

Thus, random mutation and natural selection are not only insufficient to build new systems, structures, and entire categories of organisms, but they are also actively working against such development!


Scientists have observed many beneficial mutations, and these are often publicized as proof of Darwinian evolution. However, mutations can beneficial without being constructive. In the vast majority of all cases, these mutations help by breaking or eliminating an existing system that is currently getting in the way. They help in the current environment, but they are not steps toward building anything new. In fact, the extreme effectiveness of these kinds of destructive yet beneficial mutations actually causes natural selection to work against macroevolutionary development rather than for it. When we recognize that beneficial is not the same thing as developmental or constructive, many Darwinian arguments not only lose their luster but are sometimes even turned on their head and wind up pointing against the Darwinian narrative they are alleged to support.



1 (Accessed 10/5/2022)

2 (Accessed 10/04/2022)

3 Daniel Lieberman, The Story of the Human Body (Knopf Doubleday Publishing Group, 2013) 206

4 (Accessed 10/04/2022)

5 (Accessed 10/06/2022)

6 A. E. Wilder, The Scientific Alternative to NeoDarwinian Evolution (TWFT Publishers, 1987) xi

7 Michael Behe, Darwin Devolves (HarperOne, 2019) 186

8 Michael Behe, Darwin Devolves (HarperOne, 2019) 172

9 Michael Behe, Darwin Devolves (HarperOne, 2019) 187

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