Śyāmasundara: Before, we were discussing Descartes and Hume. Descartes expressed that all knowledge comes through innate ideas, and Hume said just the opposite: "No. All knowledge comes from sense experience." So Kant is trying to unify the two ideas.
Prabhupāda: Yes. Sense experience. Sense experience means purified sense experience. That is seva. Just like I am seeing here Kṛṣṇa, but others will see a stone. So he is also seeing with his eyes; I am also seeing with the eyes, but my eyes are different from his eyes. Premāñjana-cchurita-bhakti-vilocanena (Bs. 5.38). When the eyes are anointed with love of God, ointment of love of God, then he can see. Just like if one's eyes are diseased, if he applies some eye ointment, or lotion, then he sees. So the same senses, the same eyes, unless they are treated and purified, he cannot understand or he cannot see or he cannot know.
Śyāmasundara: He says that thoughts without content are empty, meaning that the mind must have senses in order to fill its thoughts with content; and perceptions without exceptions are blind. In other words, sense impressions without thought are blind.
Prabhupāda: That thought comes from transcendental knowledge. Thought comes from higher authorities. That is called parokṣa. Then with your senses, when you try to understand, that is called aparokṣa. Then adhokṣaja. As I told you, there are five stages of acquiring knowledge: direct perception, pratyakṣa; parokṣa, receiving knowledge from higher authorities; then apply your senses, come to some conclusion, that is aparokṣa; then transcendental knowledge, adhokṣaja; then aprakṛta, spiritual knowledge.