让大模型推理变随机,才能真正理解它的认知能力
Stochastic CHAOS: Why Deterministic Inference Kills, and Distributional Variability Is the Heartbeat of Artifical Cognition
- 反对确定性推理,主张用分布多样性捕捉模型真实能力
- 单次确定输出会掩盖模型脆弱性和罕见危险行为
- 适合关注模型可靠性与安全性的研究者和开发者
确定性推理在经典软件中是理想范式:相同输入必得相同输出。随着大语言模型进入实际部署,这一理念被直接移植到推理系统中。近期思辨机器实验室的研究表明,批处理不变核与确定性注意力可实现逐比特相同的输出,将确定性推理视为可复现性与企业可靠性的前提。本文持相反立场:对大语言模型而言,确定性推理实为杀手——它扼杀了不确定性建模能力,抑制了涌现特性,使推理固化为单一脆弱路径,并通过隐藏尾部风险削弱安全对齐。大语言模型本质上是对输出的条件分布建模,而非固定函数。将分布坍缩为单一最优输出看似可靠,却系统性遮蔽了人工认知的核心属性。我们提出Stochastic CHAOS框架,将分布变异性视为可度量、可控制的信号。实证显示,确定性推理具有系统误导性:单样本确定性评估低估了模型的能力与脆弱性,掩盖了改写与噪声下的失败概率;与涌现能力相关的相变现象在贪心解码下消失;多路径推理在确定性骨干上退化,导致准确率下降与诊断信息减少。最终,确定性评估还低估了安全风险,因罕见但危险的行为仅在多样本评估中显现。
原文摘要 · Abstract (English)
Deterministic inference is a comforting ideal in classical software: the same program on the same input should always produce the same output. As large language models move into real-world deployment, this ideal has been imported wholesale into inference stacks. Recent work from the Thinking Machines Lab has presented a detailed analysis of nondeterminism in LLM inference, showing how batch-invariant kernels and deterministic attention can enforce bitwise-identical outputs, positioning deterministic inference as a prerequisite for reproducibility and enterprise reliability. In this paper, we take the opposite stance. We argue that, for LLMs, deterministic inference kills. It kills the ability to model uncertainty, suppresses emergent abilities, collapses reasoning into a single brittle path, and weakens safety alignment by hiding tail risks. LLMs implement conditional distributions over outputs, not fixed functions. Collapsing these distributions to a single canonical completion may appear reassuring, but it systematically conceals properties central to artificial cognition. We instead advocate Stochastic CHAOS, treating distributional variability as a signal to be measured and controlled. Empirically, we show that deterministic inference is systematically misleading. Single-sample deterministic evaluation underestimates both capability and fragility, masking failure probability under paraphrases and noise. Phase-like transitions associated with emergent abilities disappear under greedy decoding. Multi-path reasoning degrades when forced onto deterministic backbones, reducing accuracy and diagnostic insight. Finally, deterministic evaluation underestimates safety risk by hiding rare but dangerous behaviors that appear only under multi-sample evaluation.
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