I haven't read it but I'm asking for a quick answer.

As far as I know, Terence McKenna's theory of evolution in humans main concept is that a hominid has tried in their diet psilocybin mushrooms, and the experience they integrated changed their mind in a way that led to "us."

  • $\begingroup$ to call it a theory is seriously stretching the term. it barely qualifies as a hypothesis. $\endgroup$
    – John
    Jan 28, 2021 at 5:52
  • $\begingroup$ @user1136 I know of no paleontologist working on hominids who takes it seriously, it sets out to explain something that does not need explaining and does so with bad outdated psychology and just so stories. Worse it ascribes behaviors as unique to humans that we no are not, and that non existent uniqueness is what it pretends to explain. It is not based on any paleontological evidence, and even the author of the study it cites for the effects the mushroom criticize it for grossly misreading the effects of said mushrooms. $\endgroup$
    – John
    Jan 28, 2021 at 16:12
  • $\begingroup$ How can one theory refute another theory? And you haven’t read it? And nobody has removed this in seven years! Let’s do it! $\endgroup$
    – David
    Jan 29, 2021 at 20:21

4 Answers 4


Briefly the "Stoned Ape theory" posits that psychoactive Psilocybin mushrooms in the diet of pre-Homo sapiens primates catalyzed the change Homo sapiens. It suggests that the mushrooms conveyed selective benefits to consumers of the mushrooms, dissolving the 'egos' of our ancestors and allowing them to form communities. It may also be sexual stimulant, goes the theory and so may have conveyed an advantage there.

I think this theory is not terribly popular now, but it is difficult to refute or to prove. The only real proof would be to take a hominid or any other species and give them the fungus and see if they become intelligent. Just because this has not happened does not disprove the theory. the only other way to prove this really would be to have a time scope and look back and see what happened. Its a similar question as to how life emerged on Earth. We have some interesting evidence but conclusive proof is going to be hard to get.

I found a large collection of supporting evidence. Even the definition of human intelligence and whether it is so unique is subject to debate. Certainly there are other primates who appear to be as or more social than we. I think other theories seem as or more likely.

Darwin's theory of evolution doesn't refute many theories of how something happens in evolutionary history. The Panspermia hypothesis is taken quite seriously at this point - could it be that life originated elsewhere then was introduced here by meteorites. The origin of Species doesn't have a lot to say about that. I think the same is true for the emergence of human intelligence, which at this point we believe is unique on Earth. Hard to make an irrefutable theory based upon a single example.

  • $\begingroup$ its fairly easy to refute, since the author of paper it cites on the effects of mushrooms has criticized it for completely misinterpreting the effects, and the timeline it predicts as well as the changes it posits do match the paleontological record. its refuted for the same reason a theory that humans coevolved with wolves 8 millions years ago is refuted, it doesn't match the fossil record in the slightest, regardless of the reasoning. $\endgroup$
    – John
    Jan 28, 2021 at 16:28

Refute? No.

Shigeta summarized the work pretty well, and though I have my own opinions on McKenna's theory the fact is that Darwin and McKenna are not opposed. The "Stoned Ape theory" is a specific idea for how human intelligence might have appeared from earlier hominids. Darwin (and Wallace) proposed a broad theory that has borne out for the process of evolution by natural selection. Evolution applies to populations large and small, whether human, primate, or bacterial.

Evolution, however, is not particularly predictive and would say nothing about what might happen should some primates eat some entheogens. McKenna's idea could fit into reality, although as Shigeta said it is difficult to prove, but there is technically no Darwinian reason why it couldn't have happened. Darwin did write about human evolution in The Descent of Man.

  • 1
    $\begingroup$ a belated thanks for the props... - 8 years later...lol $\endgroup$
    – shigeta
    Jan 29, 2021 at 17:24

The stoned ape "theory" ("we owe our very existence as a species to psychedelics") isn't theory, despite it's pretense. There is no support for it in evidence, or in theory. Nor can there be because in its own terms it defies both. It's founder seems to have thought himself a genius, and solicited a cult-like following determined to spread his message, as their own. He had no college-level science education - see facts and citations below (*).

Bear in mind the "theorist's" target audience when he wrote Food of the Gods. Not scientists nor anyone scientifically literate. In his own words: "[The target audience is] the 18-25 year old group that is drug-friendly but has no rationale except that it's a good time" (Gracie, Zarkov & McKenna interview).

As for his understanding of evolution, the scope of his grasp, here's what he thought science says - if you believe what he says. No harm to have smelling salts in easy reach if you're minimally educated in biology, i.e. high school level:

"Conventional evolutionary theory tells us that small adaptive changes eventually become genetically scripted into the species" (OMNI interview)

Obviously that's 180 degrees backward from true or accurate, a recitation of what Lamarck thought - over 200 years ago, and before anyone ever heard of Darwin, or natural selection.

There's nothing theoretical in the "stoned apes" storyline, despite its claim. It's not a theory, its malarkey of the same type as Creationism - but from the opposite fringe: new age psychedelia, not old time religion.

(rolls eyeballs)

*TM was at quite a disadvantage for science ed. For any major in college, even liberal arts - there's normally a 'general studies' science requirement. Its a minimal basic in higher ed, across the board. But TM's college program (Tussman Experimental) is one that specifically, uniquely excluded science. And short-lived as it was, the college was roundly criticized in its day on that very point. Its founder made excuses, e.g. this quote (from Tussman's book EXPERIMENT AT BERKELEY):

"It is recognized that the program does nothing in the way of integrating science with the social sciences and humanities. We leave this two-culture problem for wiser men to solve. In this respect, however, our students are either better OR WORSE OFF than others" (caps added for emphasis).

Obviously lame? Colleagues in education didn't buy it. For example, this remark from Sidney Rosen (Univ of Illinois): "By his admission that he cannot find a way of integrating scientific ideas into a basic two-year program, Mr. Tussman is guilty of contradicting the educational goals he defends ... It is difficult for me to see how the curriculum can flourish without science as an integral part." - Journal of Research in Science Teaching 7: 271 (1970)

Prescient? The college didn't flourish, it floundered. It was already crashing when Rosen wrote that. In fact, the 'experiment' seems to have perhaps been a case of politics in education, masquerading as 'educational reform.' TM himself offers an interesting remark along just such lines:

"... it was an experimental program... this thing called the Tussman Experimental College. I arrived at Berkeley the year after the Free Speech Movement ... in an effort to keep the place from blowing sky high they had told this left-wing professor that he could have an experimental section of the university" (www.tripzine.com/listing.php?id=terence1)

This is the kind of info those who think they're all into McKenna, all about his rap and 'ideas' - have no clue. Zero, none. Knowing anything whatsoever, that's able to be factually established, double-checked and verified as true and accurate, valid - ain't its ticket.

  • $\begingroup$ Hi, whilst I wasn't involved in the original editing of your answer please be aware that the Stack Exchange model allows anyone to submit edits for peer review. Please refer to this page for further help. $\endgroup$
    – Rory M
    Nov 25, 2013 at 21:49
  • $\begingroup$ Thank you for the page link. After reading it along with your comment, I can only conclude the policy you cite - as explained - is critically unclear and suborns tampering with posts, such as has happened with mine. Thanks to your page link, I see five criteria specified for edits. And I find that what was done with my post - violated not one, or two of them - but all five: $\endgroup$
    – user4962
    Nov 26, 2013 at 11:30

The other answers have done excellent job explaining how the stoned ape theory contradicts the Darwin's own theory of human origins. What remained unmentioned is that Darwinism have been the basis of the modern evolutionary theories for more than a century, and in this modern light there are even more glaring contradictions between the McKenna's theory and the reality.

More specifically, there is little to support this theory from the point of view of molecular and population genetics. One could imagine two scenarious here:

  • Consumption of the psychoactive mushrooms was a single event that triggered a germline mutation in the most-recent common anscestor of the modern homo sapience (pretty much in the same way as cancerous mutations are known to be triggered by exposure to toxic substances). Note that this scenario, tracing our ancestry to a single mutant, already contradicts the McKenna's picture of a mushroom consuming prehistoric culture. Moreover, divergence of species requires more than a single mutation, and it is improbable that multiple beneficial mutations could have arisen this way.
  • The psychoactive mushrooms could have been a part of the diet of homo erectus throghout hundreds of thousands of years - sufficient time for accumulating enough mutations to evolve into a separate species. While these mutations could make humans more adapted to surviving while being stoned, they are no replacement for mushrooms. In other words, the effect of mushrooms would disappear once their use was discontinued, leaving a species with a doubtful benefit of adapted to survival while being stoned (any evidence that drunk or stoned people are less likely to harm themselves in dangerous situations is at best anecdotal).

Let us finally note that McKenna's time scale for homo sapience diverging from homo erectus (100,000 BCE) is at odds with the established paleontological scales. In fact, it even post-dates the humans common ancestor with Neanderthals and Denisova people (about half a million years ago), which is attested on genetic level for both neandertals and densova people.

  • $\begingroup$ @user1136 I think that the only way it may not contradict the modern synthesis is, if we assume that homo sapiens had already existed as a species capable of consciousness, and the mushrooms only served to wake this consciousness. This is even more so for language, since it requires specific physiological particularities, which many apes simply do not possess. $\endgroup$
    – Roger V.
    Jan 28, 2021 at 14:55
  • 2
    $\begingroup$ @user1136 I don't know that there are many, if any, serious neuroscientists who would claim consciousness is in any way unique to humans. There is no gap. $\endgroup$
    – Bryan Krause
    Jan 28, 2021 at 15:40

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