Chronological Snobbery

C. S. Lewis defines what he calls "chronological snobbery" as "the uncritical acceptance of the intellectual climate common to our own age and the assumption that whatever has gone out of date is on that account discredited."

But, he says,

You must find why it went out of date. Was it ever refuted (and if so by whom, where, and how conclusively) or did it merely die away as fashions do? If the latter, this tells us nothing about its truth or falsehood. From seeing this, one passes to the realization that our own age is also "a period," and certainly has, like all periods, its own characteristic illusions. They are likeliest to lurk in those widespread assumptions which are so ingrained in the age that no one dares to attack or feels it necessary to defend them. 

—Surprised by Joy: The Shape of My Early Life (New York: Harcourt Brace & Company, 1955), 207-208.