Biological perfection is shuddering, because it is equivalent to the same kind of organisms have no mutation, the evolution process loses momentum. We accept biological diversity, but we assume that perfection is the desired and accessible goal of physical and engineering science. Originating from our thorough understanding of many simple problems, and "simple" often means ignoring defects. This passage mainly supports the view that:. ['Perfection cannot be achieved scientifically.', 'Biological science is more profound than physical and engineering science.', 'Defects are absolutely necessary for the entire technological civilization of mankind.', 'Perfection is desirable and accessible in physical and engineering sciences.']