One of the fascinating things about the Probability Zero project is the way that the desperate attempts of the critics to respond to it have steadily led to the complete collapse of the entire evolutionary house of cards. MITTENS began with the simple observation that 9 million years wasn’t enough time for natural selection to produce 15 million fixations. Then it turned out that there were only 6-7 million years to produce 20 million fixations twice.
After the retreat to neutral theory led to the discovery of the twice-valued variable and the variant invariance, the distinction established between N and N_e led to the recalibration of the molecular clock. And the recalibration of the molecular clock led, inevitably, to the discovery that the evolutionists no longer have 6-7 million years for natural selection and neutral theory to work their magic.
And now they have as little as 200,000 years, with an absolute maximum of 580,000, with which to work. And they still need to account for the full 20 million fixations in the human lineage alone, while recognizing that zero new potential fixations have appeared in the ancient DNA pipeline for the last 7,000 years. Simply pulling on one anomalous string has caused the entire structure to systematically unravel. The whole system proved to be far more fragile than I had any reason to imagine when I first asked that fatal question: what is the average rate of evolution?
So if your minds weren’t blown before, The N/N_e Distinction and the Recalibration of the Human-Chimpanzee Divergence should suffice to do the trick.
Kimura’s (1968) derivation of the neutral substitution rate k = μ rests on the cancellation of population size N between mutation supply (2Nμ) and fixation probability (1/2N). This cancellation is invalid. The mutation supply term uses census N (every individual can mutate), while the fixation probability is governed by effective population size Ne (drift operates on Ne, not N). The corrected substitution rate is k = μ × (N/Ne). Using empirically derived Ne values—human Ne = 3,300 from ancient DNA drift variance (Day & Athos 2026a) and chimpanzee Ne = 33,000 from geographic drift variance across subspecies—we recalibrate the human-chimpanzee divergence date. The consensus molecular clock estimate of 6–7 Mya collapses to 200–580 kya, with the most plausible demographic parameters yielding 200–360 kya. Both Ne estimates are independent of k = μ and independent of the molecular clock. The recalibrated divergence date increases the MITTENS fixation shortfall from ~130,000× to 4–8 million×, rendering the standard model of human-chimpanzee divergence via natural selection mathematically impossible by an additional two orders of magnitude.
There are a number of fascinating implications here, of course. But in the short term, what this immediately demonstrates is that all the heroic efforts of the evolutionary enthusiasts to somehow defend the mathematical possibility of producing 20 million fixations in 6.5 million years were utterly in vain. Because, depending upon how generous you’re feeling, MITTENS just became from 10x to 45x more impossible.
Here is the correct equation to calculate the amount of time for evolution from the initial divergence for any two lineages.
t = D / {μ × [(N_A/N_eA) + (N_B/N_eB)]}
Where:
- D = observed pairwise sequence divergence
- μ = per-generation mutation rate (from pedigree data)
- N_A= census population size of lineage A
- N_B = census population size of lineage B
- N_eA = effective population sizes of lineage A (from historical census demographics)
- N_eB = effective population sizes of lineage B (from historical census demographics)
Which, by the way, finally gives us the answer to the question that I asked at the very start: what is the rate of evolution?
R = μ(N/N_e) / g
This is the number of fixations per site per year. It is the rate of evolution for any lineage from a specific divergence, given the pedigree mutation rate, the census-to-effective population size ratio estimated from historical census demographics, and the generation time in years.
And yes, that means exactly what you suspect it might.

