#atom
The idea that most concepts can be easily explained into simpler parts, allowing anyone of any intellectual background to understand anything if properly explained and divided.

Richard Feynman's Learning Technique is based on explaining complex phenomena as if you were explaining it to a child.

Descartes help in his 1622 treatise Des Homines, that non-human animals could be reductively explained as automata, or biological robots.

Reductionism is often contrasted with holistic and systems-based approaches which don't simply look at complex phenomena as the sum of separate parts, but also prioritize the interactions and relationships between parts, and the emergent properties that systems have independent of their parts. Rel: Emergence Theory