LONDON — This week my wife took our four teenagers and me to see the newest Indiana Jones flick, “Indiana Jones and the Kingdom of the Crystal Skull.” The movie has a promising beginning set in the Cold War, in which the KGB and the FBI compete to become the principal villains. But no sooner has Harrison Ford left America for the lost world of the Peruvian jungle, than Steven Spielberg takes leave of his cinematic senses. We are to believe that the Incas worshipped aliens from outer space who arrived in flying saucers.

Anyone of my age, 50, will remember that these intergalactic divinities first landed 40 years ago in Erich von Däniken’s book and film, “Chariots of the Gods.” Most archaeologists never paid this theory the least attention, but like the equally preposterous “The Da Vinci Code” — a book and a movie — it is so suggestive as to be impervious to refutation, at least among the credulous.

At some level, indeed, too many people’s idea of what a civilization is derives from Hollywood caricatures. In every Indiana Jones film, there comes a moment when the archaeologist enters the secret tomb or temple, which is invariably a picturesque treasure trove, but which crumbles at the first contact with modernity.

Unfortunately, the status now enjoyed by much of what constitutes the substance of our own civilization mirrors this Indiana Jones view of the past. The daunting complexities and accumulated wisdom of a civilization with its Greek-Roman and Jewish-Christian roots are no longer seen as integral to our own world, but as mere useless lumber, randomly accumulated in a dusty old warehouse, like the one depicted in the new movie.

Anything older than the Enlightenment is an encumbrance, according to this scale of values, and even the last two or three centuries have meaning only as prolegomena for the present.

This “cultural amnesia,” as the critic Clive James calls it, might matter less in a society that is staunch in defense of its own civilization. Ours, however, is not. Contempt for the achievements and traditions of the West is hard-wired into education and popular culture. There is little respect for the intellectual virtues on which our superiority depends, and still less for those who defend the West.

Yet our values, though potentially universal, are not necessarily shared; and our achievements may be turned against us. One example: because the West has failed to halt Iran’s drive to make nuclear bombs, 13 other neighboring countries, fearing Iranian nuclear blackmail, have embarked on their own civilian nuclear programs. The most dangerous region in the world, the Middle East, is hell-bent on nuclear proliferation. The danger that such weapons will be used has increased immeasurably.

In other words, we need not only to enjoy the benefits of our civilization, but also to defend it. For our political leaders to have the confidence to nip threats, our elite must abandon a self-denigrating, even suicidal version of history that denies the intellectual superiority of the West as if it were a fraud.

Our ancestors had no such inhibitions. The Victorian historian Henry Thomas Buckle understood the crucial importance of the intellect in explaining the disparity between the West and the rest. He wrote a celebrated “History of Civilization in England” (1858), designed to prove “that the progress Europe has made from barbarism to civilization is entirely due to intellectual activity.” Buckle thought “the gigantic crimes of Alexander and Napoleon become after a time void of effect … The discoveries of genius alone remain: it is to them that we owe all that we now have, they are for all ages and all times. … “

Buckle’s view of civilization — as the product of intellectual activity — may now seem naïve, but it was very influential for at least a century after his death in 1862. (Buckle died in Damascus of a fever, crying: “My book, my book! I shall never finish my book!” I know just how he felt.)

As well as civilization, Buckle believed in democracy. He thought that progress depended not only on the amount and direction of the knowledge of the intellectual elite, but also on “the extent to which the knowledge is diffused, and the freedom with which it pervades all classes of society.”

Just as in Buckle’s day, the press remains the primary vehicle for that diffusion of knowledge, and in particular, the cultural and political magazine.

Today sees the launch of Standpoint, of which I am proud to be the founding editor. This transatlantic monthly, which will be sold in America as well, sees its mission as the celebration and defense of Western civilization. Its definition of civilization includes science and religion, poetry and history, art and music, humor and gravitas.

Mr. Johnson is the editor of Standpoint magazine, standpointmag.co.uk.