To live, a man has to act. To act, he has to choose between alternatives. To choose he has to evaluate his options. To evaluate his options, he needs a purpose and a standard. To define a purpose, to discover a standard, to evaluate anything, he needs thought. The results of thought are ideas. The results of generalizing ideas are principles. The result of integrating principles is a philosophy. A lack of appreciation for philosophy is a lack of appreciation for what it takes to live.
No man can afford not to have a philosophy. It is impossible to start thinking ground up about each aspect of each concrete involved in each decision. If a man has not made the effort to form and hold an explicit philosophy, he ends up acting on ideas borrowed from others by chance. To choose not to form an explicit philosophy is to surrender life to chance. To choose to hold an inconsistent philosophy is to choose death.