In addition, Regan's most effective argument in defense of his right to life view is that infants and the severely retarded do not share certain traits. Regan cites those traits as, "(a) all and only human beings have the capacity to reason, or (b) all and only human beings have the capacity to make free choices, or (c) all and only human beings have a concept of "self," or (d) all and only human beings have all or some combination of the previously mentioned capacities" (Regan 205). He concludes that any attempt to make a distinction between humans and non-human animals would result in the grouping of infants and the severely retarded with non-human animals, and thereby subject them to the same lack of rights. Regan explains, "if we want to insist that they have a right to life, then we cannot also maintain that they have it because they satisfy one or another of these conditions. Thus, if we want to insist that they have and equal right to life, despite their failure to satisfy these conditions, we cannot consistently maintain that animals, because they fail to satisfy these conditions, therefore lack this right" (206). It is with this argument that Regan justifies his joint grouping of humans and other animals.
Regan has taken care to assure that his arguments are valid, though the ideas he introduces encourage objections. He suggests that infants and the severely retarded, without question, do not share adult human traits that would set us aside from other animals. One objection that he does not address is that infants and the severely retarded are the exception to the human species, and not the rule. The vast majority of all humans possess those traits that may widely be considered superior. A healthy, full grown human has intelligence and capabilities far beyond those of a cow who is also healthy and full grown. Also, a severely handicapped non-human animal may not even make it through a full month of life due to the disability, whereas humans can be assisted through life and in some cases, cured altogether.
