<Li> The "brain" of society - as - such (including the publicly held body of science); and </Li> <Li> The adaptive immune system . </Li> <P> In the Ashby - and - Cybernetics tradition, the word "trial" usually implies random - or - arbitrary, without any deliberate choice . </P> <P> However amongst non-cyberneticians, "trial" will often imply a deliberate subjective act by some adult human agent; (e.g. in a court - room, or laboratory). So that has sometimes led to confusion . </P>

In the trial and error theory of learning law of effect is also known as