The purpose of using one's mind is to gain understanding and clarity about reality. To this end, some methods are more effective then others. The term 'fundamentals' is based on the idea that some details are more important than others by their ability to convey understanding. For instance, the fundamental difference between man and other animals is our conceptual nature. Although there are myriad differences in shape, size, and abilities, this one difference specifies the most important difference. It is fundamental because this one difference has the largest impact on our lives. It is the cause of why we treat the two groups in very different ways.

The term "fundamental" is also highly contextual. The above examples of humans being different from other animals is based on an ethical context. When choosing how one is to act in relation to humans or animals, the conceptual nature is the difference that is most important. However, if the discussion was about biology, and the specific topic was disease tolerance, the conceptual nature of man is not important. The difference then may be the specific workings of the immune system.

Discussing ideas in terms of fundamentals is important for clarity. One cannot integrate ideas that have nothing in common. Similarly, a non-fundamental differentiation will form a concept that is unusable. Without dealing in fundamentals, it is difficult or impossible to reach useful conclusions. The effectiveness of one's thinking is dependent on thinking clearly in fundamentals.