Although thinking can occasionally lead to exciting discoveries, the stage between these discoveries is a great test of the thinker's energy and endurance. When we think, we don't have to tell ourselves that we are going through an exciting process, but it is enough to realize that we are acting in a serious, rational and self-disciplined manner in accordance with the requirements of the human condition.
the main meaning of the paragraph?
Thinkers don't just think about problems for the sake of an exciting process