Vaisesika Sūtra 3.2.18

अहमिति मुख्ययोग्याभ्यां शब्दवत् व्यतिरेकाव्यभिचाराद् विशेषसिद्धेर्नागमिकः ॥१८॥

Since "I" by primary and suitable usage does not deviate and is established due to its distinct speciality, and is not inferable.