In 22 days millions of people will clink glasses and kiss each other at midnight to celebrate the advent of a new half century. Millions of others will sneer and say that they should have celebrated this momentus event a year ago.

The dispute which simmered for several weeks last year about whether 1950 or 1951 marks the mid-century point, has started again. Nor is this sort of argument a new thing. One of the few defeats that Kaiser Willhelm H of Germany ever suffered before he blundered into the first wolrld war occurred when a board of scientists reversed an imperial dictum proclaiming that the year 1900 was the beginning of the twentieth century. The experts told the Kaiser that he had a year to wait.

This year scientists are no longer so prepared to venture information. The University Observity, for instance, claims that whether 1950 is or is not century 20 1/2 is all a matter of definition.

"It's an arbitrary thing," the Observatory said, "how can you tell from the stars . . . they go on and on and on."

Staff members in the mathematics department suggested it is a literary rather than a scientific argument. Their department is split on the question.

The root of the problem seems to be whether centuries should be calculated absolutely on a mathematical basis or whether concessions to logic should be made to usage. If logic is enforced, the mid-century won't be until 1951 because since there is no year zero, a year wasn't up until the year two began.

Others argue that history is hany about whether there was a year zero or not and claim that as long as the matter is in doubt, it's just as well be consider a century as having started when the last two digits are zeroes.

The Aztees and the Mayans didn't have this sort of a problem, Benjamin D. Paul, assistant professor of Social Anthropology, pointed out. They reckoned time spans in 52 year cycles, at the end of which they had a massive celebration around a four aided temple, each of which had a 52 stop stairway leading up to it. When the celebration was over, they started a 52 year stretch all over again.