Descartes used to say: ” I think therefor I am”, or “I exist” thought is powerful and it’s the proof that we exist in some way, but there’s another thing more important is to be conscious, “I observe therefor I am conscious”. There’s a difference between “thinking” and “observing” and what is the best way of our conduct of understanding.
Most of people suffer from too much thinking, they search for a way out of this zone of thinking, you know that we can’t stop thinking and feeling, and Descartes was right in his quotation , because we exist through our thoughts and feelings. When Descartes said his famous phrase, he wasn’t thinking of it, but he was observing his thoughts and feelings when they come in his mind, may be he was in meditation and he concluded this expression when he was conscious of his thoughts and feelings.
The same thing happened with several scientists, they observe some phenomena and they test it, and they make some theory and proof its truth, like Newton, Einstein, Galileo,..etc. You observe things is powerful than you think about them, we can see clearly if we observe things more deeply without too much thinking, start now doing that and your life will transform entirely.