Tools as "petrified memes": A duality.

Tools are generated by defined steps, fulfill distinct uses, and elicit affordances or mental representations. When the latter are recombined, they are perceived as "technical reasoning," resulting in novel tools when executed. They can be exchanged, varied, and selected between individuals in a cumulative social process. Tools are materialized, "petrified" memes forming a duality within the framework of active externalism.