This paper introduces EVOLM, an innovative framework for self-evolving language models that improves performance without relying on human annotations or external teacher models. By transforming a model’s internal knowledge into explicit natural-language rubrics, the system creates an autonomous feedback loop where evaluation and generation capabilities improve in tandem. This method utilizes variational inference to optimize rubric generators, rewarding criteria that successfully help a small, frozen judge distinguish between superior and inferior responses. Experimental results demonstrate that EVOLM outperforms established baselines, including GPT-4.1, by shifting from abstract judgments to verifiable, instance-specific criteria. Ultimately, the research shows that structuring evaluative capacity into co-evolving rubrics allows models to surpass the limitations of static external supervision.