Einstein's famous theory that E = mc2 has been shown to be true by modern physics.
I studied practical linguistics to become an ESL teacher, but some other people in my classes were studying theoretical linguistics in order to do research.
Theoretically speaking, the planet Mars
appears to have had most of the conditions necessary to support simple life forms at least at some point in time, but no evidence of life past or present has yet been found on the planet.
Einstein once remarked: "If the facts don't fit the theory, change the facts."
Mark Russell once joked, "The
scientific theory I like best is that the rings of Saturn are composed entirely of lost airline luggage."
Efforts to solve global problems often require broad theoretical understanding of cultural systems, as well as detailed understanding of specific local cultures.
The notion of the Big
Bang theorizes that the universe began as a huge explosion of matter.
In 1872, a professor of physiology said that Louis Pasteur's theory of germs was a ridiculous fiction.
Einstein said that a unified super-theory of everything would enable us to "read the mind of God."
Someone once joked, "Given a choice between two theories, take the one which is funnier."
There are some holes in his theory which haven't been explained as of yet.
We will be examining three theoretical perspectives on the question during the next few days.
Benedict Spinoza once said that if facts conflict with a theory, either the theory must be changed or the facts.
Current theories trace our first human ancestor to Africa about 5 to 7 million years ago.
Someone once remarked that the quickest way to kill a good theory is to put it into practice.
Current theory in anthropology holds that Neandertals became extinct only 30,000 years ago, and co-existed with modern humans in Europe.
Friedrich Engels once noted that an ounce of action is worth a ton of theory.
Many theorists now believe that vocabulary development is even more important than grammar study for second language learners.
A leading political theorist suggests that despite opposition to the plan, the government has no choice but to proceed with legislation.
Musical theorists of the Middle Ages worked hard to develop an adequate musical notation.
Whether the Romans made any significant contributions to the theory or practice of music is unknown.
The notion that human beings are systematically taught how to behave, feel and think is the basis of sociological theory.