Practical reason

"'In theory, there is no difference between theory and practice. But, in practice, there is.' -- Jan L. A. van de Snepscheut"

In philosophy, practical reason is the application of reason to real-world decision-making (ie. deciding on a course of action). Contrast this with theoretical reason (often called speculative reason) which is concerned with absolute and universal truths. For example: deciding exactly how to build a telescope is practical reason, whereas deciding between two theories of light and optics is speculative reason.

In cognitive research, practical reason is the process of ignoring unproductive possibilities in favor of productive possibilities. It is considered a form of cognitive bias, because it is illogical. An example would be calling all hospitals to look for your missing child, but not checking morgues, as finding his corpse would be 'counter-productive.'