Models of consciousness should account for the phenomenology of subjective experience, including perceptual illusions. The Moon Illusion is a paradigmatic example that has yet to be accounted for. The Moon often appears larger near the perceptual horizon and smaller high in the sky, though the visual angle subtended is invariant. We show how this illusion can result from the optimization of a 3D projective geometrical frame through free energy minimization, following the principles of the Projective Consciousness Model. The model accounts for all documented modulations of the illusion without anomalies (e.g., the “size-distance paradox”), surpasses other theories in explanatory power, makes sense of inter- and intra-subjective variability vis-à-vis the illusion, and yields new quantitative and qualitative predictions. Empirical data from a virtual reality experiment support the predictions of the model. We also discuss how the model suggests explanations for other relevant illusions, concerning objects both at far and nearer distances, including the sky dome illusion, illusions of perceived size observed in the context of crowding experiments, and the Ames Room illusion.

意识模型应说明主观经验的现象学，包括知觉错觉。月亮幻觉是一个尚待说明的范例。尽管对向的视角是不变的，但月亮通常在感知层附近显得较大，而在天空中则较小。我们展示了这种幻觉如何通过遵循投影意识模型的原理通过自由能最小化来优化3D投影几何框架而产生的。该模型说明了所有记录的幻觉调制，没有异常（例如，“尺寸-距离悖论”），在解释力上超过了其他理论，使主体间和主体内的变异相对于幻觉有意义，并且产生新的定量和定性预测。来自虚拟现实实验的经验数据支持模型的预测。我们还将讨论该模型如何为其他相关错觉提供解释，涉及远近距离的物体，包括天穹错觉，在拥挤实验中观察到的感知大小的错觉以及艾姆斯房间错觉。