Theory

What is your view of theory?! Would you say that nothing is as practical as a good theory? Or would you call upon an old proverb: Action will remove the doubt that theory cannot solve?
 
Do you like going to the theatre to see a movie or a play? You might be surprised to learn that the words theatre and theory have the same origins.
 
The word theory, from the Proto-Indo-European (PIE) root dhau (to see), is the source of Greek theatron (to see or to view), theatrum (theatre), and the English word theatre, a place where we go to see something in order to learn or to be entertained (Notice that -tre follows the Greek spelling rather than -ter).
 
Greek theatron is also the source of Greek theoros (spectator) and theoria (contemplation, speculation, theory). A person (theoros) who looked thoughtfully or with intention at some thing or some experience could learn or understand (theoria).
 
Theoria passed unchanged into Latin, came to Old French as theorie, and in the 1590s came to English as theory (conception, mental scheme). By the 1610s, theory meant the underlying principles of a science or art.
 
By the 1630s, theory also meant an intelligible explanation for something which is based on observation and reasoning, a plausible explanation or belief about something.
 
When we look carefully at or beneath a set of facts or a body of evidence, what do we see? We see, or can see, theory.
 
There is another connection to PIE dhau (to see). Not only is dhau the source of the word theory, dhau is also the source of Greek thauma (a wonder or a miracle). Sometimes understanding and learning something can seem miraculous, an unexpected “Aha! I see. Now I get it!”
 
Reference: Online Etymological Dictionary, https://www.etymonline.com/
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