theory: Declaration argued about an absolute truth, based simply on suspicion, or alien evidence. Explanation of pragmatic a set of knowledge, or issues related to the topic itself, to be shown with a scientific method through practice. Example: music theory is an elementary explanation, that demands a pragmatic check supported in the immediate execution of the ideal instrument, according to the scientific method. A method to learn to play a given instrument, requires the same imminent, as teaching instruments available.