Critical Thinking
The art of analyzing and evaluating thinking with a view to improving it (Foundation for Critical Thinking).
Epistemology
The theory of knowledge, especially with regard to its methods, validity, and scope. Epistemology is the investigation of what distinguishes justified belief from opinion (Wikipedia).
Knowledge
That, which is discovered and used to change one's life or the life of others.
Learning
The process whereby knowledge is created through the transformation of experience (Kolb, Experiential Learning; Experience as the Source of Learning and Development).
System Thinking
A set of synergistic analytic skills used to improve the capability of identifying and understanding systems, predicting their behaviors, and devising modifications to them in order to produce desired effects (Arnold and Wade, 2015)