 Another example of explanatory reduction is due to Marcel Weber (2005). In line with models of theory reduction, Weber maintains that biochemical (“physico-chemical”) laws carry the explanatory force, but that a fact or basic generality about biological mechanisms (rather than a genuine law or a whole theory), such as the mechanism of action potentials in neurotransmission, is what is explained. By permitting reference to higher level structures in the explanans, such as axons, he does not require that a reductive explanation contain exclusively biochemical expressions.