Life is defined by Maturana and Varela as a type of self-organization: autopoiesis in the physical space. This resembles the concept of me- tabolism, which itself is typically included in definitions of life. Three senses of metabolism are distinguished. If life depends on either auto- poiesis or metabolism (in the third sense), then strong A-Life is impos- sible. The theory of autopoiesis challenges concepts familiar in biology and cognitive science. While its use of informational language is too restrictive, its use of cognitive language is too liberal: life does not imply cognition.