“Reductionism can either mean (a) an approach to understanding the nature of complex things by reducing them to the interactions of their parts, or to simpler or more fundamental things or (b) a philosophical position that a complex system is nothing but the sum of its parts, and that an account of it can be reduced to accounts of individual constituents.”
and
“The limit of reductionism’s usefulness stems from emergent properties of complex systems which are more common at certain levels of organization.”
From the Wikipedia definition for “reductionism”:
“Reductionism can either mean (a) an approach to understanding the nature of complex things by reducing them to the interactions of their parts, or to simpler or more fundamental things or (b) a philosophical position that a complex system is nothing but the sum of its parts, and that an account of it can be reduced to accounts of individual constituents.”
and
“The limit of reductionism’s usefulness stems from emergent properties of complex systems which are more common at certain levels of organization.”