The errors with Bret Weinstein’s four-part test of adaption

A biologist I admire, Bret Weinstein, employs a four-part test to determine whether a trait is the product of evolution.

  1. Is it complex?
  2. Does it have a cost?
  3. Is there variation in the amount of cost that is spent?
  4. Does it persist over evolutionary time?

If a trait has all of those characteristics, then it is adaptive.

Weinstein’s thesis is both cogent and general. It is conceptually logical that anything costly, if it persists over time, must be paying for itself.

Weinstein’s insight here is cause why he, his wife, and biologists of a similar stripe are often accused of “anthropomorphizing” the process of evolution. They talk about how evolution “gave humans” so and so adaption for our benefit. “Evolution is no grand planner”, detractors say. Perhaps the negative reaction to creationist straw man arguments is what is fueling this reflexive hatred of anything approaching anthropomorphizing. But in that reflexive hatred is the implication that evolution is an arbitrary process, which it is not; it merely makes use of semi-random mechanisms. There are distinct differences between what is designed and what is adapted – but there are also distinct similarities. The non-technical linguistic distance between these concepts is not well instantiated, forcing one to default to “design” language when discussing those aspects of adaption that intersect with those of design.

What is groundbreaking about this observation is that it reveals how virtually every trait of organisms is evolved.  If a trait exists, and is present across generations, it almost certainly has some cost in resources or energy, compared to its not existing at all. Moreover, everything in biology is more complex than it appears at first glance. Accordingly, such traits are evolved, and thus serve a purpose. Nature is not arbitrary, at least not as much as one might think.

This fact, to me, was always frustratingly apparent. Academics, desperate to avoid discussion of biology, will often scour for any opposing explanation of human behavior, any explanation other than “it’s biology, it’s not arbitrary, and it actually serves a purpose”.

Any discussion of spousal cheating, racism, or gender roles, for instance, is just platitudes, unless it dives into the underlying causes rooted in biology.

But Bret Weinstein’s true insight is that his four-part test can assess any structure with a lineage, not just carbon-based ones.

He uses the example of religion.

“Religion passes the adaptive test. It’s complex, it’s expensive, there’s a variance in how much creatures spend on it, and it lasts over evolutionary time”.

One could say that all human institutions pass the adaptive test. Weinstein once said, to paraphrase, that one of the most unique things about humans is that we have exported much of our adaption to the “cultural layer”. Businesses, political parties, customs, languages, nations, and finally, religions. These are all things that meet his four criteria.

Proponents of New Atheism ask, “why can’t we design our own moral systems, rather than using the moral systems of people who lived two thousand years ago?” What they miss is the distinction between what is designed and what is evolved. Religions are not static, but changes unrecognizably with time. Everything (yes everything) that we associate with culture was never designed; it evolved, and has been continually evolving until the present day. Culture is influenced by everyone who touches it.

So it is a type of arrogance to proclaim that you can personally design a better system than of comprised of all that accumulated wisdom. At least that would be true if Weinstein’s theory was without error. But the title of this post says otherwise. So what’s the problem?

It is possible that Bret Weinstein addressed the following objections elsewhere; this post is specific to the video.


Is a parasite an evolved trait? They are complex organisms. They have a cost to their host (they feed off human blood). There is a variation in how much humans have genital lice. And they may not be very common any more, but in the stone age they were extremely common and persisted for thousands of years. Genital lice would seem to check all boxes in the test of evolution.

The astute reader may note that genital lice are evolved — just not for the benefit of humans, but for the benefit of themselves. They are outside structures that impose themselves on hosts, who would prefer to live without them.

So my example of genital lice doesn’t discredit the adaptive test; they aren’t a human trait strictly speaking. Perhaps the proclivity for lice is a human trait, but that is a different question.

A “trait” is something is something that is passed from parent to offspring. A tapeworm does not spread from person to person in that manner. Just because your father had a tapeworm does not mean you will have a tapeworm.

Here is the reason I bring this up: can the same not be said about social institutions?

Bret Weinstein would probably respond to the anarcho-capitalist by describing how state governments survive his adaptive test, and are therefore evolved to the betterment of society. I would grant him governments are evolved, in a sense. But to the betterment of society — that is not established. Like genital lice, state governments might be their own evolving structures, imposing themselves on humans (with or against the interests of the humans themselves).

It may be coherent to call state governments “evolved”, but that does not mean they are evolved by humans and for the benefit of humans. There is a semantic issue: is a government a human “trait”? Perhaps. Or maybe religions may be simply hitchhiking off the proclivity of humans to engage in culture more generally.

As stated before, a trait is something that passes form parent to offspring. Governments don’t really spread that way. So no, a government is not a human “trait” in a strict sense.

I believe that humans and governments are (almost always) in a symbiotic relationship. Humans and religions are only sometimes. But this is a separate conversation.

Most of the time, evolved institutions survive by monopolizing zero-sum resources I discussed previously. Businesses monopolize talented people. Governments monopolize land, mainly. Religious, by contributing to community, take advantage of network externalities.


My comparison to parasites might work for the example of state governments. However, it does not hold true about religion. This is because Weinstein might respond that, unlike parasites, religion is passed directly from parent to offspring. Fair enough. For my disagreement to hold, I must have some other objection.

Weinstein has in the past, I believe incorrectly, asserted that every religious practice must have provided some benefit to have survived in an evolved framework. The problem is that some evolved systems can afford to be inefficient. I will explain.

Consider businesses.

In a perfectly competitive landscape, businesses must be ruthlessly efficient to stay afloat.  If a business has nothing to set it apart, it can only out compete other businesses by counting every penny and being exceptionally well run. This is true of restaurants, for example; most restaurants shut down because they are not run competently enough.

The opposite is true of monopolies. If a business has no competition, it does not need to be ruthlessly efficient to stay afloat. Peter Thiel makes this point. In the early days of Google, the motto Don’t be Evil was more than just a slogan; it could have hurt profits, but Google could afford it because it was a monopoly. Twitter may be a terribly run company, but they stay afloat because monopolize space via network externalities.

Religions have a significant barrier to entry, arguably even more so in the past when they used stricter mechanisms to hold on to followers. Religions require adherence, which, as I have discussed before, can be monopolized. This created an environment where the biggest religions went relatively unchallenged.

And something is a monopoly, it can avoid having its every property being selected for or against. Logically, if something does not have to compete, it doesn’t matter if it develops less-than-perfect properties; it is guaranteed to survive until it literally cannot carry its own weight.

Given this, not every aspect of religion is an optimized adaption, because it doesn’t need to be. The biggest religions are successful enough that they can afford counterproductive practices.

Outpacing Biology

I have one final remark. I have discussed masturbation before because it is a perfect example of how one aspect of our biology (the gratification of the orgasm) can out-pace another aspect of our biology (our intelligence and hand dexterity). Individually evolved parts of the organism combined in ways evolution could not predict to yield a suboptimal result. Masturbation meets all four criteria of the adaptive test, so it is indeed evolved. The mistake is to conflate “evolved” with “aiding survival and reproduction”.


If you thought any of this was interesting, you will probably like my other posts even more:

2 thoughts on “The errors with Bret Weinstein’s four-part test of adaption

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s