Materialistic scientists, they are studying the brain substance, but what is this brain substance? This is also matter. Brain substance actually do not work. That is something else. That is, that information is being given here: dehino 'smin yathā dehe (BG 2.13). Within this body there is the proprietor of the body. Just like, what is that computer machine? Very subtle machine. Or this tape recorder, or any other . . .
Nowadays so many subtle machines are manufactured, and they are working very wonderfully. Just like the television machine, it has no connection with . . . where or anything, and still exactly the photograph, the sound and everything is coming from outside, and you are seeing in your room things as they are, even with color. So it is very subtle machine undoubtedly. But the subtle machine is working not independently. They . . . there is a man who is working on the . . .
Suppose if I am put before such subtle machine, I cannot work unless I am very expert in handling such machine. So the machine is not very important. Real important is . . . importance is given to the person who is handling the machine. Similarly, this machine, this body, this is also a machine, and it has been described in the Bhagavad-gītā as a machine: yantrārūḍhāni māyayā.