Opening the methodological black box of research synthesis in language education: where are we now and where are we heading?

What do we mean by 'research synthesis'? full discovery will be made, if the inquirer be competent, conduct his researches with knowledge of the discoveries already made, and make them his starting-point; but anyone who, casting aside and rejecting all these means, attempts to conduct research in any other way or after another fashion, and asserts that he has found out anything, is and has been, the victim of deception.