IPA: /ˌæntiˈræʃənəlɪzəm/
KK: /æntiˈræʃənəlɪzəm/
A belief or philosophy that rejects the idea that reason and logic are the primary sources of knowledge and understanding.
Antirationalism challenges the notion that human reason can fully explain the complexities of life.
Antirationalism is formed from "anti-" (meaning against) and "rationalism" (from Latin "rationalis", meaning reasonable or logical, and "ratio", meaning reason). The term describes a belief system that opposes or critiques the principles of rational thought and reason.
Think of 'against' ('anti-') the idea of being 'reasonable' ('rationalism') — that's what antirationalism means.