In plain words
There is one power that fills everything everywhere. Such an all-powerful Ātma principle stands in every man in subtle form. What is the reason man cannot recognise such a divine power? Relying on the strength of body and mind, relying on the strength of wealth, gold, goods and vehicles, man forgets his own true nature, takes the physical, mundane world alone as his support, and because he is full of Ahaṅkāra he keeps forgetting this Ātma principle.
At times the senses are merely things seen. All of these have taken on an inert form. The eyes see this object. This is merely something seen. When they see it, the eyes are the seer. But the eyes, the seer at this moment, themselves become something seen at another moment. How do they become the seen? Even when the eyes are open, because this mind is wandering somewhere, the eyes cannot see even the things right in front of them. So at that moment the eyes become the seen. The mind turns into the seer. At another moment the mind itself becomes the seen. Buddhi takes the form of the seer. In a state where there is no power of enquiry, the mind becomes the seen and Buddhi turns into the seer. In a state where there is no power of enquiry, the mind becomes the seen and Buddhi turns into the seer. That is, in the state of sleep there is no mind. The mind takes the form of something merely seen. But Buddhi stays shining in the state of awareness. So at that time Buddhi is the seer and the mind the seen. In the state of samādhi, Buddhi too becomes the seen. The Ātma turns into the seer. So for all things the Ātma alone is the seer. This mind and the senses, all of them are only the seen. That is why all of these were given the name karaṇas. They are only tools. There is a seer who does this work and has it done. If that seer himself is not there, then however valuable the tools may be, all of them become useless. Spending some crores of money, they brought in a big machine and set it up. Its value is great indeed. But if there is no current in it, it becomes a useless lump of iron.