 Carruthers presents a clear outline of the first type of argument “the biological argument for massive modularity”: “(1) Biological systems are designed systems, constructed incrementally. (2) Such systems, when complex, need to have massively modular organization. (3) The human mind is a biological system and is complex. (4) So the human mind will be massively modularly in its organization” (Carruthers 2006, 25). An example of this argument is to appeal to the functional decomposition of organisms into organs “designed” for specific tasks, e.g. hearts, livers, kidneys. Each of these organs arises as a result of natural selection and the organs, acting together, contribute to the fitness of the organism. The functional decomposition is driven by the response to specific environmental stimuli. Rather than natural selection acting to produce general purpose organs, each specific environmental challenge is dealt with by a separate mechanism. All versions of this argument are arguments from analogy, relying on the key transitional premise that minds are a kind of biological system upon which natural selection acts.