WASHINGTON. — Edward Gibbon, historian and wit, was dryly funny even in his footnotes, such as this one on giraffes:
'' . . . the tallest, the most gentle and the most useless of the large quadrupeds. This singular animal, a native of only the interior parts of Africa, has not been seen in Europe since the revival of letters.''
Was it mere coincidence or did the quickening of Europe's intellectual life actually cause the departure of the giraffes? Did they have an aversion to learning?
Gibbon was having fun with the historian's chore of discerning the causation behind events. Today some historians want to don white smocks and enlist science in their search for such explanations.
A government museum, which possesses some of Lincoln's hair, blood and skull fragments, may allow scientists to try to clone Lincoln's tissue for analysis of his DNA, which is the determinant of heredity. What will this enable historians to explain? Not much.
Scientists might determine whether Lincoln suffered from Marfan syndrome. Many victims of that disorder are tall and gangly and susceptible to sudden heart failure. Lincoln was 56 when assassinated, older than most l9th century Marfan victims lived to be. But suppose he had the syndrome. So what? Establishing that he had it would shed no light on history because it would not justify inferences about the causes of historic actions.
Perhaps someday science will be able identify a genetic cause ** of chronic depression and will establish that Lincoln was afflicted. But note the adjective ''chronic.''
We know Lincoln often was melancholy and depressed. It would have been odd if he had not been, living in a city infested with spies, inundated by reports of military debacles and national fratricide.
Anyway, for cloning to reveal something of historic importance the something would have to pertain to a mental impairment of personality pattern. Some people believe ''genes define the essence of the person.'' But what is essential?
I believe persons are what they read.
Certainly physical facts about individuals can cause large historic effects. Perhaps (it would be nice to think so) Napoleon's hemorrhoids really did have some determining effect on his conduct at Waterloo. And there is evidence that a medical fact may have been the cause of a century-shaping effect.
Last spring Arthur Link of Princeton, biographer of Woodrow Wilson, received a large number of documents from the son of the man who was Wilson's personal physician at the time of Wilson's fight with Congress over ratification of the Versailles Treaty. Mr. Link says the papers show that Wilson suffered cerebrovascular disease long before his 1919 collapse that occurred while campaigning for ratification of the Treaty and membership in the League of Nations.
Wilson, says Mr. Link, was afflicted by hypertension, intermittent small strokes and vascular incidents that interfered with brain functioning, beginning perhaps as early as 1896. His intransigence and occasional incoherence during the Treaty debate (in conversation with the Senate Foreign Relations Committee he made at least 30 errors of memory) may have been symptoms of this physiological problem, not, as many historians have concluded, signs of defects of character or political skills.
Today it is considered ''democratic'' to write history ''from the bottom up'' rather than ''the top down,'' discounting the importance of the distinguished few. The very idea of individual greatness is considered problematic, perhaps absurd and certainly politically incorrect. The consciousness of individuals, or classes, or nations, or even entire ages is routinely written about as the ''reflection'' of more ''real'' causes.
The art of biography already is suffering the ravages of psychobiographers who reduce their subjects' convictions to neuroses and ascribe to their subjects motives severed from ideas. May we at least be spared explanations of Lincoln's genius, or the ''essence'' of any individual, in terms of genetics.
George F. Will is a syndicated columnist.