Here, I review the physics meaning of optimization, knowledge and design evolution, and why these concepts and human activities are profoundly useful for human life. A law of physics is a concise statement that summarizes a phenomenon that occurs in nature. A phenomenon is a fact, circumstance, or experience that is apparent to the human senses and can be described. The design in nature phenomenon facilitates access for everything that flows, evolves, spreads, and is collected: river basins, atmospheric and ocean currents, animal life and migration, and technology (the evolution of the “human-and-machine species,” wealth, life). This phenomenon is summarized by the constructal law: the occurrence and evolution of designs in nature, its time direction. Based on its record, the constructal law accounts for the design phenomenon and also for all the phenomena that have been described individually (ad-hoc) with end-design (destiny) statements of “optimality” (min, max). Most notably, the constructal law accounts for contradictory end-design statements such as minimum entropy production and maximum entropy production, and minimum flow resistance and maximum flow resistance.