The text mentions the triad of 'seen, seer, and seeing' vanishing. What does this philosophical concept mean?

This concept, described in Chapter 35, refers to a state of non-duality in devotion. Normally, we experience the world through a triad: the seer (the person experiencing), the seen (the object of experience), and the seeing (the act of perception itself). The text suggests that in deep devotion to Sai, these distinctions collapse. The devotee becomes so absorbed that the sense of a separate self who is seeing, hearing, or tasting vanishes. The chapter explains that this applies to all senses, such that when a word is heard, the triad of 'the heard, the hearer, and the hearing' shatters, and only Sai's form manifests. This ultimate state of absorption where all actions dissolve is referred to as attaining the state of non-action (Naishkarmya).