Why is it important to have a system for exchanging currencies between nations? to encourage trade to encourage new business to protect small businesses to stop the rising cost of products

Why does c. wright mills identify critical thinking as one of the most important criteria for the development of intellectual craftsmanship? why is constantly being aware of the biased nature of your reactions and interactions (what c. wright mills calls self-reflexive) key to the development of that critical thinking? finally, why is keeping a file important, how can it lean to intellectual curiosity which can foster critical thinking and to develop a keen analytical mind?