| … | … | @@ -707,6 +707,61 @@ failing at large — rather than merely producing some rise. It is Gánti's chem |
| 707 | 707 | field's standing answer; the contribution is testing it against our own measured claim that isolation |
| 708 | 708 | is insufficient, and finding that it supplies exactly the half isolation could not. |
| 709 | 709 | |
| 710 | ### Test A — and the size threshold turns out to be a proxy |
| 711 | |
| 712 | Prompted by a literature check rather than by another guess. The relatedness literature holds that a |
| 713 | **single-cell bottleneck** is what suppresses cheaters in multicellularity — *"development from a |
| 714 | single-celled zygote resets relatedness among cells to its maximum value each generation"* — and a |
| 715 | zygote is the **n=1 limit of a small compartment**. Prediction: a single-unit bottleneck should |
| 716 | rescue the failing large-compartment arms. |
| 717 | |
| 718 | Implemented as a reproduction mode. **Propagule**: the offspring is ONE randomly chosen unit, which |
| 719 | may equally be a parasite — nothing selects which buds. **Fission**: the existing 50/50 split. Only |
| 720 | offspring *variance* differs. |
| 721 | |
| 722 | | division size | fission | fis control | **propagule** | prop control | |
| 723 | |---|---|---|---|---| |
| 724 | | 4 | 11.68 | 6.36 | 11.67 | 6.34 | |
| 725 | | 8 | 11.45 | 6.00 | 11.51 | 6.05 | |
| 726 | | 16 | 7.65 | 5.76 | **11.13** | 5.82 | |
| 727 | | 32 | 5.86 | 5.62 | **7.94** | 5.66 | |
| 728 | |
| 729 | **The confound, and the check that resolves it.** Propagule mode *also* shrinks realized compartment |
| 730 | size (4.95 vs 6.34 at division size 16; 7.33 vs 12.25 at 32), so a rescue at matched division |
| 731 | *threshold* could be nothing but smaller compartments arriving by another route. The first verdict |
| 732 | claimed variance outright and was **overclaiming**; it was replaced with a matched-size comparison |
| 733 | over a 9-point sweep, interpolating fission: |
| 734 | |
| 735 | | matched mean size | propagule | fission (interp) | advantage | |
| 736 | |---|---|---|---| |
| 737 | | 2.5 | 11.59 | 11.60 | **−0.01** | |
| 738 | | 3.1 | 11.51 | 11.51 | **+0.00** | |
| 739 | | 3.7 | 11.40 | 11.18 | +0.22 | |
| 740 | | 4.2 | 11.33 | 10.47 | +0.87 | |
| 741 | | 4.9 | 11.13 | 8.15 | **+2.98** | |
| 742 | | 5.3 | 10.54 | 8.03 | +2.51 | |
| 743 | | 5.6 | 9.18 | 7.91 | +1.27 | |
| 744 | | 7.3 | 7.94 | 6.64 | +1.30 | |
| 745 | |
| 746 | Mean advantage at matched size **+1.14**, and the *shape* is the argument: **exactly zero at sizes |
| 747 | ≤3**, where a 50/50 split already *is* a bottleneck and the two modes coincide, rising to **+2.98** |
| 748 | where they differ most in offspring variance. A pure size effect would be flat at zero throughout. |
| 749 | The φ-blind control stayed flat in propagule mode at every size, so this is selection and not a |
| 750 | demographic artifact of the reproduction mode. |
| 751 | |
| 752 | > **Compartment size was never the operative variable. Assortment variance was, and size was only a |
| 753 | > proxy for it.** |
| 754 | |
| 755 | This reframes what `ribozyme.c` measured: "compartments must be small" was never about size — small |
| 756 | compartments were simply the only way that model had to generate high assortment variance. Given |
| 757 | variance directly, large compartments work (11.13 at division size 16, against fission's 7.65). And |
| 758 | it is the first time in the arc that a model result and an external empirical literature converged |
| 759 | on a mechanism, each arrived at independently: our size threshold and the single-cell bottleneck of |
| 760 | every obligate multicellular lineage are the same thing at different scales. |
| 761 | |
| 762 | Recorded caveat: after widening the sweep to 9 sizes the program's printed small/large crossing |
| 763 | counts have wrong denominators; the matched-size table is the actual test and is unaffected. |
| 764 | |
| 710 | 765 | ### Where Part C leaves rung 1→2 |
| 711 | 766 | |
| 712 | 767 | **Narrowed to one thing.** The circle that stood since the 14-experiment arc — privatization needs |
| … | … | @@ -724,7 +779,10 @@ anything in Part C. |
| 724 | 779 | So the ladder's asymmetry has a cleaner explanation than the one Part C opened with: **boundary |
| 725 | 780 | formation emerges wherever the boundary is a consequence of the chemistry rather than an investment |
| 726 | 781 | in it** — 3→4 free between-compartment selection, 2→3 free concatenation, and now 1+4 via growth |
| 727 | | coupling. What does not follow from any of it is a faithful modular copy. |
| 782 | coupling. Test A adds the quantity that governs whether it *works*: not how big the compartment is |
| 783 | but **how much variance its reproduction generates among offspring**, which is why every obligate |
| 784 | multicellular lineage independently evolved a single-cell bottleneck. What does not follow from any |
| 785 | of it is a faithful modular copy. |
| 728 | 786 | |
| 729 | 787 | Honest bound on the linkage result: 2→3 is the rung where privatization was *least* contested to |
| 730 | 788 | begin with. The principle it demonstrates is real; the rung was the easy one; and it does not |
| … | … | @@ -755,6 +813,11 @@ transfer to 1→2 on its own — only Law 2 does. |
| 755 | 813 | - **Compartment-level selection need not be supplied** (`chemoton.c`) — coupling growth to the |
| 756 | 814 | chemistry's own output generates it with no fitness-proportional sampling anywhere, reproducing the |
| 757 | 815 | decreed version's size-threshold signature (PARTIAL: small 2/2, large 1/2). ✓ |
| 816 | - **Assortment variance, not compartment size, is the operative variable** (`chemoton.c` Test A) — |
| 817 | a single-unit propagule beats a 50/50 split by +1.14 φ at *matched realized size*, with the |
| 818 | advantage exactly zero where the two modes coincide (size ≤3) and peaking at +2.98 where they |
| 819 | diverge most. Our size threshold and the single-cell bottleneck of obligate multicellularity are |
| 820 | the same mechanism at different scales. ✓ |
| 758 | 821 | |
| 759 | 822 | **Open (field-wide, not just here):** |
| 760 | 823 | - **rung 1→2 (metabolism → heredity)** — genuinely unsolved; our null echoes it. `template.c` isolates |