An argument is brewing between the physicists who study elementary particles and those who study solid state matter, complex systems made of many interlocking parts. The ultimate goal of elementary particle research is a few simple equations that will describe how subatomic particles interact to produce all that is. Looking for explanation of the whole by understanding its basic parts is reductionism.
Solid state physicists believe that this approach is insufficient and will not give the answers sought. Many forms of matter cannot be described in terms of fundamental particle interactions. When systems become very complex they appear to be irreducible and completely new and independent laws emerge. Complex systems display novel emergent behavior, obeying higher organizing principles that cannot be further simplified.