Critical Thinking
The art of analyzing and evaluating thinking with a view to improving it (Foundation for Critical Thinking).
Cronbach alpha
Cronbach's alpha is a measure used to assess the reliability, or internal consistency, of a set of scale or test items. In other words, the reliability of any given measurement refers to the extent to which it is a consistent measure of a concept, and Cronbach's alpha is one way of measuring the strength of that consistency. See more here: Virginia stat Consulting or here (Wikipedia).
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).