I thought this section of the transcript from their first video was worth noting because it shows that neither Dr. Hancock nor Matthews is capable of doing their own math properly. I mean, forget correcting mine or even understanding the proper context, Hancock doesn’t even do his own math properly. Matthews, of course, can’t follow what he’s doing, so she can’t offer any potential corrections to his math, let alone to mine:
I had to clean up Dr. Hancock’s transcript because the literal transcript is incoherent due to how he’s working through the numbers on a white board and would paint him in an unfairly bad light in written form. But I think I did it fairly and correctly; if you doubt the accuracy of my cleanup, you can certainly watch the relevant portion of the video or read the uncorrected transcript from the time-stamped link instead. If you do spot any inaccuracies, let me know and I’ll correct them.
Hancock: (1:50:45) Under neutral theory, the mutation rate equals the substitution rate. That’s Kimura’s foundational result: k = μ. So with that the mutation rate is going to equal the substitution rate. But in this context we want to know a number of mutations instead of necessarily a rate. And so if we just then multiply this by L, by the length of the genome, that then tells us how many mutations we expect to see right, ,and by the same token, how many substitutions we expect to see right um and so if we take a mutation rate the human mutation rate has been estimated in a range. I’m going to use the lower end, about 1.2 × 10⁻⁸ per site per generation. The haploid genome is 3.2 gigabases. Multiply those together and you get approximately 76.8 new mutations fixing in the population every single generation.
Quick correction here — I initially used the diploid genome size of 6.4 gigabases, which was an error because fixation occurs on the haploid genome. However, the number still works, because Perkay et al. 2025 estimated total de novo mutations — including structural variation, not just SNPs — at between 98 and 206 per generation. The average is 152. Divide by two for the haploid count and you get 76. So the number holds.
Now, already, notice the problem with Vox Day’s model. He showed 180 mutations over 252,000 generations. I’m getting 76.8 in a single generation. He’s off by orders of magnitude.
To put this in context, compare humans to bacteria. Bacteria have the lowest mutation rate observed in life, about 10⁻¹¹, and very small genomes. When you multiply those together you get about 4 × 10⁻⁵ mutations fixing per generation — far less than one. Under neutrality it takes bacteria roughly 22,000 generations to fix a single mutation. Humans are fundamentally different: our genome is much larger and our mutation rate is much faster. We fix many mutations every generation. Day is using bacterial-scale numbers for a human-scale genome.
Now, we’re interested in divergence between humans and chimps, not fixation within a single population. Since both lineages have been accumulating mutations independently since they split, we need to account for both branches. The total expected divergence is 2Tμ, where T is the divergence time in generations.
So: 2 × 252,000 generations × 76.8 mutations per generation gives us approximately 38.7 million fixed differences. And when you look at the actual data for single-nucleotide differences between humans and chimps, it’s right in that range — about 35 to 40 million. That’s back-of-the-napkin math landing within the confidence interval of what sophisticated statistical models produce. The neutral model works.
Now, I can already hear the objection: the real number is 205 million differences, not 38 million. Day cites Yoo et al. 2025 for this figure. But that number includes gap divergences — insertions, deletions, duplications, inversions — where a single mutational event can change tens, hundreds, thousands, even millions of base pairs at once. You cannot interpret that through a single-nucleotide mutation rate. A point mutation rate applied to structural variation isn’t just difficult — it’s inappropriate.
That said, let’s see what it would take. If we solve for the mutation rate needed to produce 205 million differences in 504,000 lineage-generations, we get about 407 mutations per generation — roughly five times the observed SNP rate. Initially I thought that was preposterous, but on reflection, if you account for the mutation rate across every kind of variant — duplications, deletions, inversions, all of it — maybe it’s close to that number. So even taking Day’s high figure, it’s still within biological reality. Like this is not an abnormally no species has this this kind of rate. So my point is that we can account even for the highest end of the mutational differences with a model that assumes that selection was not involved at all. And I think that’s like I don’t know that to me that’s a nail in the coffin of his entire argument
Matthews: 100%. Because this effectively what this is doing is saying, okay, like even if we use your absolute bonkers assumptions, if we use the model that is actually appropriate instead of making up coefficients and throwing them into equations that aren’t meant for this this type of population, it it still doesn’t debunk evolution and it still doesn’t debunk the the typical divergence time. But it’s it’s you know I’ll I’ll mention we know that’s not correct because again we have just bona-fide examples of organisms that everyone would accept as related who clearly have differences that are the in so far as we can know anything the direct result of duplications of or deletions of large um like hundred thousand you know million long long base pair sequences. Um, so but that’s crazy because again just to to dumb this down for for people like me, um, his math is wrong, his assumptions are wrong, but even if you take both of those and use the correct model, it is still within biological reality to use Zack Hancock’s phrasing.
Hancock: Yeah. Even the highest end like if we if we pick his 205 million mutations I think that still falls again. It’s wrong but I think it still falls within realms of mutation rates that we have seen especially if you try to add in like instead of just the rate of single nucleotide polymorphisms you add in all possible rates maybe you could get to something like that.
Matthews: Yeah that’s that’s absolutely insane um wow layers layers of incorrect and it’s still it’s still feasible how about we see how he tries to shrug off this exact concept. Let’s take a little look see and and then we’ll sort of we’ll sort of wind down here. Um that’s just that’s crazy to me.
Error 1: k ≠ μ: Neutral substitution is applied incorrectly
Hancock is citing the textbook correctly. Under neutral theory, the mutation rate equals the substitution rate. That is Kimura’s foundational result: k = μ. This means that although the vast majority of individual neutral mutations are lost to drift, new ones enter the population fast enough that the rate of fixation exactly equals the rate of mutation.
What Hancock, like every other population geneticist, has failed to understand that “eventually” in this case means “infinity”. Fabio Chalub of the Universidade Nova de Lisboa proved it in 2022. This is why Kimura’s foundational result CAN NEVER be utilized in any calculation that involves a finite time period. It’s also why Kimura provided a separate equation for calculating how long it takes for a neutral mutation that enters a population to fix given the very low chance it fixes in any time prior to infinity. I appear to have been the first to combine his two equations into one more practical one:
VD: ∫₀ᵀ F_X(u) du = T − ∫₀ᵀ (1 − F_X(u)) du ≈ T − 4Nₑ
So Hancock’s entire approach is doomed to failure from the start. But he didn’t even do his own inapplicable math correctly, which I shall now demonstrate.
Error 2: The Diploid Genome Error and the Fake Correction
This is where Hancock gets his own math wrong. Setting aside that he clearly doesn’t know k ≠ μ over a period of 6.3 million years, he doesn’t even get his own math right or account for things he previously addressed, but admitted that he doesn’t understand.
Hancock multiplied the per-site mutation rate (1.2 × 10⁻⁸) by the diploid genome size (6.4 Gb) to get 76.8. He caught the error in editing — “we can’t use 6.4, this is the diploid genome size, you fix on a haploid genome, so it should be 3.2 × 10⁹” — which means the correct number is 38.4 mutations per lineage per generation, not 76.8.
He then tried to rescue the wrong number by citing Perkay et al. 2025, which estimates 98–206 de novo mutations per diploid individual per generation (average 152, halved to 76). But this is sleight of hand. The Perkay number includes structural variants — insertions, deletions, duplications — not just SNPs. Hancock’s entire calculation is explicitly about single-nucleotide differences, using a single-nucleotide mutation rate. You cannot validate a SNP-only calculation with a number that includes structural variation and call it a correction. It’s mixing units.
Worse, even if the Perkay number were applicable, 152 de novo mutations per diploid individual divided by 2 does not give you the quantity the divergence formula requires. The formula 2TμL uses the haploid genome’s site count because you’re computing substitutions per site summed across unique sites. The de novo count per individual (76.8) counts mutations across both chromosome copies in a single individual. The substitution rate across the genome per lineage (38.4) counts the rate at which distinct sites accumulate changes. These are different quantities. Hancock replaced the right one with the wrong one and used an unrelated paper to justify keeping the error.
The consequence cascades through everything that follows. His divergence calculation — 2 × 252,000 × 76.8 = 38.7 million — is incorrect even before we account for the way his entire calculation assumes d = 1, the complete generational replacement every generation of the Wright-Fisher model. Hancock explicitly discarded d in the earlier video because he “didn’t know what it was.” Well, this is exactly what it’s for. That’s why he kept 252,000 post-CHLCA generations, which are observably not the effective generations available because human generations overlap. The correct figure is 201,600 at d = 0.80.
The corrected result is 2 × (252,000 x 0.80) × 38.4 = 15,482,880. But we’re not done correcting his math yet, so hold that 15.4 million.
Error 3: The Minimized Target
Neutral theory applies, by definition, to the entire genome, not just to the cherry-picked 35 million observed divergences. Hancock is treating his entire neutral prediction as if every single one of those substitutions lands on a divergent site when the divergent sites are only 1.09% of the genome. His reasoning is circular. He assumes the neutral substitutions explain the divergences, then uses the divergences as evidence that neutral substitutions occurred. But based on a truly neutral distribution, only 1.1 percent of those neutral substitutions land in the divergent zone, while the other 98.9 percent would land in regions that are either identical between the two species or unaligned and have nothing to do with the observed SNV divergence if they existed in the first place, which, of course, they don’t, because k ≠ μ.
15,482,880 × (35,000,000 / 3,200,000,000) = 169,344.
He calculated 38.7 million. The correct number is 169,344. He’s off by a factor of 228.5. I told you they were innumerate.
Error 4: The Bacterial Rate Claim
Hancock falsely claims “when Vox Day does his fixation rates he is using the mutation rate and the fixation rate for bacteria.” This is totally incorrect and betrays a complete failure to understand how MITTENS is calculated. I’m not using any mutation rates at all. I don’t need them to calculate anything because I’m utilizing observed fixation rates from the LTEE. I have a separate calculation of human fixation rates, which is about 16 times slower than the bacterial rate.
Error 5: The 205 Million Back-Calculation Is Off by 2×
Hancock calculates that accounting for 205 million differences requires ~407 mutations per generation, which he says is “about five times” the observed rate. But he’s comparing to his erroneous 76.8, not the corrected 38.4. He’s actually off by a factor of 10.6 here; even his wrong calculations are wrongly described.
Error 6: Conflating Mutation Entry with Fixation
Hancock says 76.8 mutations “enter and fix every single generation.” This is absolutely impossible. No mutation ever fixes in a single generation. Zero. Just think about it for two seconds: how would a mutation that newly arose in a boy born in Papua New Guinea fix in every single child in the world born in his children’s generation? Population geneticists have lost the connection between their abstract math and the actual physical world that their math is supposed to describe.
Error 7: Hancock’s cited rate isn’t inappropriate, it’s a category error
A point mutation rate applied to structural variation isn’t just inappropriate, it’s irrelevant to the accounting problem. The accounting problem doesn’t care about mechanisms. It asks one question: how many bases are different? Whether those differences arrived one at a time or ten thousand at a time doesn’t change the total. It doesn’t reduce the number of base-pair differences that need to be explained in some way. Hancock is confusing the rate question with the accounting question, then using his confusion about the first to dodge the second.
Error 8: Everything Matthews said
She has no idea what Hancock is saying, she has no grasp of anything that I have written, and her assertions only serve to demonstrate she comprehends none of it.
Error 9: Everything Matthews said
Seriously, it’s so bad that that it requires repeating, italicizing, and probably a larger font. She’s observably innumerate, even for a butterfly collector. She could probably just about handle the nets, but she’d definitely need an assistant to count them.
“Wow, um, that’s insane! What did we, um, catch, like ten thousand monarchs today?”
“Yeah, well, actually, it appears we got twelve, Dr. Matthews.”
“That’s just crazy!”
Error 10: My 205 million base-pair estimate for the chimp-human divergence
Now, I do have to concede one error that I definitely committed. The 205 million base-pair divergence that represents the human side of the estimated 410 million post-CHLCA human-chimp divergence is incorrect. I did the best I could with the numbers that Yoo et al reported in 2025, but since they were scattered across three different pages of an 82-page spreadsheet and the three different numbers utilized different denominators, it wasn’t even possible to get an accurate total.
So in order to find a more accurate number, I downloaded the entire genomic database of the great apes, all 25,302,032,866 base pairs that collectively make up the 7 genomes, and had the 96-core beast known as UATV1 analyze the numbers. It turned out that not only did Yoo et al incorrectly report the sizes of the chimpanzee-human and bonobo-human autosomal non-identical divergences as being exactly the same at 283,674,368 despite there being a 44,000 difference between the two, but based on the actual genomic mappings by the Consortium, the total chimpanzee-human divergence from the human perspective is 398,673,272 base-pairs, or 12.79 percent of the human genome.
I still have to complete how it looks from the chimpanzee side before doing an allocation of that difference, but at present, the most relevant number to plug into MITTENS is 199,336,636, not 205 million.
