Life Simulator

Asymmetric execution

Does complexity keep rising when only one partner's code runs? Under a host interaction the instruction pointer stays inside the first tape while both heads still range over the pair, so the second tape is pure read/write substrate and never runs a byte of its own. A tape's fate then depends on how the tapes that host it treat it as data, which is a pressure on what a tape looks like rather than only on what it does — the asymmetry host–parasite systems are built on.

Substrate
soup
Status
finished
Epochs per run
20,000
Runs finished
360 / 360
Transition rate
9 of 360 finished runs flagged by the detector (3%), 9 confirmed by a replicator

Findings resting on this sweep: Does complexity keep rising when only one partner's code runs? negative

Transition epoch vs interaction
concat host 0 5000 10000 15000 20000 Interaction Transition epoch concat: emerged at epoch 9510 concat: emerged at epoch 17200 concat: emerged at epoch 10420 concat: emerged at epoch 16880 concat: emerged at epoch 7620 concat: emerged at epoch 8170 concat: emerged at epoch 4170 concat: emerged at epoch 5880 concat: emerged at epoch 7690 concat: no emergence in 20000 epochs (171 of 180 runs) 171 host: no emergence in 20000 epochs (180 of 180 runs) 180

Filled dots are runs a replicator confirmed emerged in; the line joins the median per value. Hollow dots are crossings the detector flagged that nothing confirmed. Hollow markers at the top count the runs with no emergence in 20000 epochs, the flagged-only ones among them.

Arms of interaction
Interaction n Flagged Emerged Median epoch IQR Censored
concat 180 9/180 5% 9/180 5% 8,170 7,620–10,420 171
host 180 0/180 0% 0/180 0% — — 180

Flagged counts the crossings the transition detector reported; emerged counts the ones the replicator census or the copy rate confirmed. The median epoch and the IQR are of the confirmed emergences, the flagged median beside them in grey; a flagged crossing nothing confirmed is censored like a run that was never flagged.

Time to emergence vs interaction
0 5000 10000 15000 20000 0 0.2 0.4 0.6 0.8 1 Epoch P(no emergence) concat — 9 of 180 emerged host — 0 of 180 emerged

Each line is the estimated share of runs in an arm with no self-replicator yet at that epoch. A run that never emerged is censored where it was last watched, so it holds the line up only for as long as it was actually observed.

Emergence hazard per arm of interaction
Interaction Runs Events Run-epochs at risk Hazard per 104 epochs (95% CI) Persisted
concat 180 9 3,507,540 0.0257 (0.0117–0.0487) 9 of 9
host 180 0 3,600,000 0 (0–0.0102) —
All arms 360 9 7,107,540 0.0127 (0.00579–0.024) 9 of 9

Persisted counts the emergences whose world was still in the transitioned state at its last sample; the rest climbed back out of it and are counted as relapses.

Distinct lineages vs epoch, per arm of interaction
0 5000 10000 15000 20000 0 5000 10000 15000 20000 Epoch Distinct lineages concat host
  • concat
  • host
Share of the largest lineage vs epoch, per arm of interaction
0 5000 10000 15000 20000 0 0.01 0.02 0.03 0.04 0.05 Epoch Share of the largest lineage concat host
  • concat
  • host
Compressed length of the dominant tape (bytes) vs epoch, per arm of interaction
0 5000 10000 15000 20000 0 50 100 150 200 Epoch Compressed length of the dominant tape (bytes) concat host
  • concat
  • host
Instructions in the dominant tape vs epoch, per arm of interaction
0 5000 10000 15000 20000 0 10 20 30 40 50 Epoch Instructions in the dominant tape concat host
  • concat
  • host
Compressed length of the largest lineage's tape (bytes) vs epoch, per arm of interaction
0 5000 10000 15000 20000 0 50 100 150 200 Epoch Compressed length of the largest lineage's tape (bytes) concat host
  • concat
  • host
Instructions in the largest lineage's tape vs epoch, per arm of interaction
0 5000 10000 15000 20000 0 10 20 30 40 Epoch Instructions in the largest lineage's tape concat host
  • concat
  • host
Transition epoch vs max tape len
128 256 0 5000 10000 15000 20000 Max tape len Transition epoch 128: emerged at epoch 9510 128: emerged at epoch 17200 128: emerged at epoch 10420 128: emerged at epoch 4170 128: emerged at epoch 5880 256: emerged at epoch 16880 256: emerged at epoch 7620 256: emerged at epoch 8170 256: emerged at epoch 7690 128: no emergence in 20000 epochs (175 of 180 runs) 175 256: no emergence in 20000 epochs (176 of 180 runs) 176

Filled dots are runs a replicator confirmed emerged in; the line joins the median per value. Hollow dots are crossings the detector flagged that nothing confirmed. Hollow markers at the top count the runs with no emergence in 20000 epochs, the flagged-only ones among them.

Arms of max tape len
Max tape len n Flagged Emerged Median epoch IQR Censored
128 180 5/180 3% 5/180 3% 9,510 5,880–10,420 175
256 180 4/180 2% 4/180 2% 7,930 7,673–10,348 176

Flagged counts the crossings the transition detector reported; emerged counts the ones the replicator census or the copy rate confirmed. The median epoch and the IQR are of the confirmed emergences, the flagged median beside them in grey; a flagged crossing nothing confirmed is censored like a run that was never flagged.

Time to emergence vs max tape len
0 5000 10000 15000 20000 0 0.2 0.4 0.6 0.8 1 Epoch P(no emergence) 128 — 5 of 180 emerged 256 — 4 of 180 emerged

Each line is the estimated share of runs in an arm with no self-replicator yet at that epoch. A run that never emerged is censored where it was last watched, so it holds the line up only for as long as it was actually observed.

Emergence hazard per arm of max tape len
Max tape len Runs Events Run-epochs at risk Hazard per 104 epochs (95% CI) Persisted
128 180 5 3,547,180 0.0141 (0.00458–0.0329) 5 of 5
256 180 4 3,560,360 0.0112 (0.00306–0.0288) 4 of 4
All arms 360 9 7,107,540 0.0127 (0.00579–0.024) 9 of 9

Persisted counts the emergences whose world was still in the transitioned state at its last sample; the rest climbed back out of it and are counted as relapses.

Distinct lineages vs epoch, per arm of max tape len
0 5000 10000 15000 20000 0 5000 10000 15000 20000 Epoch Distinct lineages 128 256
  • 128
  • 256
Share of the largest lineage vs epoch, per arm of max tape len
0 5000 10000 15000 20000 0 0.005 0.01 0.015 0.02 0.025 Epoch Share of the largest lineage 128 256
  • 128
  • 256
Compressed length of the dominant tape (bytes) vs epoch, per arm of max tape len
0 5000 10000 15000 20000 0 50 100 150 200 Epoch Compressed length of the dominant tape (bytes) 128 256
  • 128
  • 256
Instructions in the dominant tape vs epoch, per arm of max tape len
0 5000 10000 15000 20000 0 10 20 30 40 50 Epoch Instructions in the dominant tape 128 256
  • 128
  • 256
Compressed length of the largest lineage's tape (bytes) vs epoch, per arm of max tape len
0 5000 10000 15000 20000 0 50 100 150 200 250 Epoch Compressed length of the largest lineage's tape (bytes) 128 256
  • 128
  • 256
Instructions in the largest lineage's tape vs epoch, per arm of max tape len
0 5000 10000 15000 20000 0 10 20 30 40 Epoch Instructions in the largest lineage's tape 128 256
  • 128
  • 256
Detector against replicator census, per arm
concat 128 concat 256 host 128 host 256 0 1 2 3 4 Arm Runs concat 128 — flagged only: 2 of 90 sampled runs concat 128 — replicators only: 0 of 90 sampled runs concat 128 — both: 3 of 90 sampled runs concat 256 — flagged only: 0 of 90 sampled runs concat 256 — replicators only: 0 of 90 sampled runs concat 256 — both: 4 of 90 sampled runs host 128 — flagged only: 0 of 90 sampled runs host 128 — replicators only: 0 of 90 sampled runs host 128 — both: 0 of 90 sampled runs host 256 — flagged only: 0 of 90 sampled runs host 256 — replicators only: 0 of 90 sampled runs host 256 — both: 0 of 90 sampled runs
  • Flagged only
  • Replicators only
  • Both

The two outer bars of an arm are its disagreements: runs the detector flagged with no replicator ever counted, and runs that counted one without being flagged.

Detector against replicator census, per arm — flagged runs held compress_ratio below 0.6, replicating runs counted at least one replicator at the locked top_k 16; the wider column re-reads the stored worlds of the same runs at top_k 64 and is blank for an arm no corpus pass has measured
Arm Sampled runs Flagged Replicators Replicators at top_k 64 Both Either but not both
concat 128 90 5 3 3 2
concat 256 90 4 4 4 0
host 128 90 0 0 0 0
host 256 90 0 0 0 0
Does complexity keep rising, per arm — the median of the last decile of each emerged run's post-crossing samples against the median of its first decile. An arm keeps rising where at least half its measured runs raise dominant_instruction_count by 20% or more without their conserved core falling, and plateaus where at least half sit within 10% of where they started. An arm clearing both bars reads mixed and one clearing neither reads neither. A run is measured on its instruction count, and its conserved core is compared in bytes, so a core that reads zero at both ends counts as a core that did not fall — the post-hoc amendment of 2026-09-21; the pre-registered rule dropped those runs as unmeasured, and the pre-registered unmeasured column counts, per arm, the measured runs it dropped. A run carrying no conserved core at all over the span is unmeasured. dominant_compressed_len is printed beside them and decides nothing: it saturates at the tape cap plus zlib's envelope, and distinct_lineages is the secondary reading of sweep 10, where an arms race shows as a late-run lineage count above the control's at the same cap. An arm reads on two measured runs, or on a blank block of ten; a steal arm whose steal_rate never left zero reads as theft that never evolved, not as theft that does not help, and one never sampled on that observable reads unmeasured
Arm Emerged Measured Pre-registered unmeasured Instructions Conserved core Compressed length Distinct lineages Rising Plateau Peak steal_rate Reading
concat 128 5 / 90 5 5 20 → 18 0 → 0 139 → 139 37 → 2 1 / 5 2 / 5 0 neither
concat 256 4 / 90 4 4 16 → 18 0 → 0 267 → 267 77 → 1 1 / 4 1 / 4 0 neither
host 128 0 / 90 0 0 — — — — 0 / 0 0 / 0 0 barren
host 256 0 / 90 0 0 — — — — 0 / 0 0 / 0 0 barren

Replicators by the orientation-aware detector

The detector reads a random sample of 256 cells of a stored world and runs each cell's tape down a chain of 5 runs against fresh noise, each copy carried into the next run. After the last run the first half holds the fourth copy, back in the tape's own orientation even for a tape that writes its reverse; the cell passes where 3/4 of its positions match the original, each position read by the majority of 5 trials. The locked census counts only same-orientation copies among the 16 commonest tapes, so it reads zero in worlds of reverse copiers. Only the worlds a run kept are read — the first and the last, one about every 1000 epochs and the one nearest the transition — so every run is read at the same cadence, and a first replicator epoch here is no finer than that. Live samples are not used. A run is measured once the corpus pass has read every world it kept; until then it counts in none of the census columns, and the pass is re-run as runs finish. A world holds replicators where at least 50% of its sampled cells pass. This is a companion reading: it relocks neither the census nor the emergence rule (#245).

Detector, emergence rule and orientation-aware census, per arm, over finished runs — the census columns count measured runs only
Arm Finished runs Measured Flagged Emerged Replicator worlds Held to the end Replicators, not emerged Emerged, no replicators Median first replicator epoch (coarse)
concat 128 90 90 5 5 5 5 0 0 ~10,000
concat 256 90 90 4 4 4 4 0 0 ~8,000
host 128 90 90 0 0 0 0 0 0 —
host 256 90 90 0 0 0 0 0 0 —

Download oriented census (CSV)

Runs

Download CSV Download transition report (CSV)

Seed Interaction Max tape len Status Priority Epochs done Transition epoch Census
71 host 256 finished 10 20,000 — — Run
72 host 256 finished 10 20,000 — — Run
73 host 256 finished 10 20,000 — — Run
74 host 256 finished 10 20,000 — — Run
75 host 256 finished 10 20,000 — — Run
76 host 256 finished 10 20,000 — — Run
77 host 256 finished 10 20,000 — — Run
78 host 256 finished 10 20,000 — — Run
79 host 256 finished 10 20,000 — — Run
80 host 256 finished 10 20,000 — — Run
81 host 256 finished 10 20,000 — — Run
82 host 256 finished 10 20,000 — — Run
83 host 256 finished 10 20,000 — — Run
84 host 256 finished 10 20,000 — — Run
85 host 256 finished 10 20,000 — — Run
86 host 256 finished 10 20,000 — — Run
87 host 256 finished 10 20,000 — — Run
88 host 256 finished 10 20,000 — — Run
89 host 256 finished 10 20,000 — — Run
90 host 256 finished 10 20,000 — — Run