<P> Four such systems are identified: </P> <Ul> <Li> Natural selection which "educates" the DNA of the species, </Li> <Li> The brain of the individual (just discussed); </Li> <Li> The "brain" of society - as - such (including the publicly held body of science); and </Li> <Li> The adaptive immune system . </Li> </Ul> <Li> Natural selection which "educates" the DNA of the species, </Li> <Li> The brain of the individual (just discussed); </Li>

Who advocated the trial and error theory of learning