The Truth Was Never Gone: Perfect Aliasing in Compliant-Context Truth Probes
Updated 46 min ago · first seen 11 Sept 2026
paper_01M294FNRKKXKXGEMVYXA0F6ST
- Published
- 11 Sept 2026
- T1 · 46 min ago
- arXiv
- 2609.10739
- T1 · 46 min ago
- Category
- cs.LG
- T1 · 46 min ago
Abstract
A truth probe fitted where truthful reporting and a task's prescribed action coincide cannot distinguish those targets from its fitting labels alone. We call this failure of semantic identification perfect aliasing. In a controlled binary reporting game, truth and prescribed-action probes fitted on compliant contexts solve the same optimization. On rival contexts their labels are complements, forcing their AUROCs to sum to one; this identity holds across 751 cell-layer pairs to floating-point precision. We separate prescribed output symbols from semantic action using randomized codebooks, then separate truth from prescribed action by fitting on mixed compliant and rival contexts. For a reward-trained Gemma-2-9B policy that answers falsely on all evaluated rival trials, the conventional probe scores $0.006 \pm 0.005$ AUROC across three training seeds, while mixed-fit probes score $1.000$ on the same held-out activations. Mixed fitting uses more training examples and access to labelled rival contexts, so this comparison establishes linear recoverability rather than isolating the benefit of decorrelation. We also show that two compliant-fit probes, both perfect in-distribution, score $0.080$ and $0.986$ on the same rival activations. The findings concern what a probe measures: they do not establish preserved functional belief, causal use of the recovered direction, or a deployable deception detector. Code and aggregate results accompany the paper.
Authors 1
Dylan Jayabahu
Specification
- Official page
Source:arXiv (Atom API + RSS)T1observed 46 min agohigh
- Arxiv announce type
- cross
Source:arXiv (Atom API + RSS)T1observed 46 min agohigh
- arXiv id
- 2609.10739
Source:arXiv (Atom API + RSS)T1observed 46 min agohigh
- Categories
- cs.LG, cs.AI, cs.CL
Source:arXiv (Atom API + RSS)T1observed 46 min agohigh
Source:arXiv (Atom API + RSS)T1observed 46 min agohigh
- Primary category
- cs.LG
Source:arXiv (Atom API + RSS)T1observed 46 min agohigh
- Published
- 11 Sept 2026
Source:arXiv (Atom API + RSS)T1observed 46 min agohigh
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46 min ago
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- Authors
- Dylan Jayabahu
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Claim history · Abstract
Abstractabstract1
| Value | Valid from → to | Status | Source | Confidence | Extractor |
|---|---|---|---|---|---|
| A truth probe fitted where truthful reporting and a task's prescribed action coincide cannot distinguish those targets from its fitting labels alone. We call this failure of semantic identification perfect aliasing. In a controlled binary reporting game, truth and prescribed-action probes fitted on compliant contexts solve the same optimization. On rival contexts their labels are complements, forcing their AUROCs to sum to one; this identity holds across 751 cell-layer pairs to floating-point precision. We separate prescribed output symbols from semantic action using randomized codebooks, then separate truth from prescribed action by fitting on mixed compliant and rival contexts. For a reward-trained Gemma-2-9B policy that answers falsely on all evaluated rival trials, the conventional probe scores $0.006 \pm 0.005$ AUROC across three training seeds, while mixed-fit probes score $1.000$ on the same held-out activations. Mixed fitting uses more training examples and access to labelled rival contexts, so this comparison establishes linear recoverability rather than isolating the benefit of decorrelation. We also show that two compliant-fit probes, both perfect in-distribution, score $0.080$ and $0.986$ on the same rival activations. The findings concern what a probe measures: they do not establish preserved functional belief, causal use of the recovered direction, or a deployable deception detector. Code and aggregate results accompany the paper. | → current | current | arXiv (Atom API + RSS)T1 | high | deterministic |
Claims are temporal and append-only: a new observation closes the previous claim (valid_to) instead of overwriting it. Conflicting claims from different sources are kept side by side and flagged — never averaged. Methodology →
The Truth Was Never Gone: Perfect Aliasing in Compliant-Context Truth Probes: arxiv announce type changed from new to cross
Arxiv announce typenew→crossarxivNew paper: The Truth Was Never Gone: Perfect Aliasing in Compliant-Context Truth Probes
arxiv
| Source | Document | Type | Tier | Last observed | Snapshots |
|---|---|---|---|---|---|
| arXiv (Atom API + RSS) | rss.arxiv.org/rss/cs.CL | feed | T1· Official | 46 min ago | 1 |
| arXiv (Atom API + RSS) | rss.arxiv.org/rss/cs.LG | feed | T1· Official | 46 min ago | 1 |
Tier 1 = official/primary, 2 = quality secondary, 3 = community, 4 = unverified. Every snapshot is archived; see all sources and the methodology.