Swami Mukundananda
Why do I make wrong decisions even after thinking carefully?
A defective mind cannot reach perfect knowledge
Going on and on thinking is not enough while the mind is full of anger, hatred, greed and illusion, because you will not be able to attain perfect knowledge. The other source is the scriptures, and the Vedic scriptures have perfect knowledge.
You can go on and on thinking, but your mind is still full of the defects of anger, hatred, greed and illusion, so you will not attain perfect knowledge.