The article advances a framework allowing for a unified description of
technical innova- tion and the advancement of theoretical knowledge. Cognitive
structures based on fore- going actions with physical objects are externally
represented by artifacts, language or writing. The exploration of actions with
these external representations such as the fabri- cation and usage of new
devices or the composition of texts opens up new possibilities for a
reflective abstraction leading to new cognitive structures. The exploration of
the options for actions is canalized by historically specific contexts
constraining the actors. Based on the example of the early history of weighing
with a focus on the establishment and differentiation of unequal-arm balances
we elaborate the consequences of such an accoun
