What is critical thinking : (1) Identifying the assumptions that frame our thinking and determine our actions,(2)checking out the degree to which these assumptions are accurate and valid, (3) looking at our ideas and decisions ( intellectual, organizational, and personal) from several different perspectives, and (4) on the basic of all this, taking informed actions. I also propose a basic typology of different kinds of assumptions that critical thinking unearths and scrutinizes paradigmatic, prescriptive, and causal.