In Book Two, Section 109 of the Masnavi, Rumi uses the metaphor of a squint-eyed (احول) person to explain how a flawed inner state distorts the perception of reality. Just as a cross-eyed individual sees a single moon as two and rejects the truth of its singularity, those with corrupt or 'crooked' hearts perceive straight truth as crooked. Rumi reinforces this epistemological principle by referencing the Quranic concept that 'corrupt things are for corrupt people' (الْخَبِيثَاتُ لِلْخَبِيثِينَ), concluding that individuals inclined toward falsehood naturally attract and accept lies while being blind to the unified truth.