The unknown is the message of the UPANISHADS.....
Upanishads are concerned with the unkown only as a beginning. They end with the unknowable. The known realm becomes science, the unknown is philosophy, and the unknowable belongs to religion.
Thinking is a quality of your inner being. What does thinking means ?
It means to retain your consiousness, to remain alert and aware , to encounter a problem. A problem is there : you face it with your total awareness. And then there arises an answer - a response.
This is THINKING ........
TRUTH is not something which can be handed over to you. You will have to raize your CONSCIOUSNESS ; you will have to come to the climax of your being . Only from there, the glimpses become possible. And when you die completely to your EGO, truth is revealed, never before.
It is not a philosophical enquiry....
It is a religious transformation.