October 25, 1983

President Reagan sent a thank you letter today to 145 House Democrats who had voted in favor of increasing the American contribution to the International Monetary Fund, thus attempting to remove a major roadblock to final Congressional approval of the increase. The Democrats had demanded the letter from the President after the Republican Congressional Campaign Committee had attacked them for voting last August against an amendement to the quota increase bill. The amendment, sponsored by conservative Republicans but opposed by the White House, would bar I.M.F. loans to ''Communist dictatorships.'' With the letter out of the way, the Reagan Administration still has to meet another condition of the Democrats for their continued support of the bill, which would increase by $8.4 billion the American contribution to the monetary fund. As a quid pro quo, the Democrats want the Administration to increase Government subsidies for housing for the poor.

News Analysis WASHINGTON, Oct. 24 - The devastating bomb blast in Lebanon has left President Reagan a man under siege, tested politically and personally more severely than at any other time in his tenure. It is clear that the past 72 hours have have taken their toll on the President. He looked exhausted, emotionally drained, even old for the first time in his Presidency when he stepped from his helicopter and reached for an umbrella in the pouring rain on the South Lawn of the White House Sunday morning. It was 8:30 A.M., six hours after he had been awakened with the first news of Marine Corps casualties. As he began to speak to reporters, he took his wife's hand seeming to need moral support. Her face showed an anguish that aides said was stirred not only by the bombing in Lebanon but also by the incident Saturday at the Augusta National Golf Club in Georgia where a gunman seized several hostages, demanding to speak to the President.

SAN FRANCISCO APROPOSAL to build a Ronald Reagan Presidential library at Stanford University in Palo Alto has prompted a campus debate. There are three parts to the proposed complex: the library and a Ronald Reagan museum, both of which would be managed by a Federal archivist at a cost of about $2 million a year to be paid by the Federal Government; and a Ronald Reagan institute on public affairs to be managed by the Hoover Institution on War, Revolution and Peace. In its present form, the proposal to locate the Reagan papers at the Hoover Institution is the product of a recently formed Hoover committee, though Mr. Reagan's longstanding links with the institution have apparently given rise to such suggestions for years. Some members of the Stanford faculty see the Hoover Institution, which was established on the campus in 1919 with a gift from Herbert Hoover of $50,000 and his papers up to that time, as a national center for conservative political activity. Earlier this year, faculty demands for change in the university-institution relationship led the Stanford trustees to create an oversight committee to consider ''matters of governance, appointments, sharing of scholarly resources and other matters of mutual interest'' between the university and the Hoover Institution.

A front-page map yesterday incorrectly located the United States Marine headquarters blown up in a terrorist attack in Beirut. The correct location is shown today in the diagram on page A12.

WHEN John Stapylton Habgood started studying and teaching science at Cambridge University more than three decades ago, he had what he considers his first religious experience - a realization that the kinetic theory of gases describes quite elegantly and accurately what the properties of a gas will be. ''It was one of the beautiful things that you are constantly finding in science,'' recalls Dr. Habgood. ''An experience of beauty, of order and of mysteries revealed.'' But gradually, as he earned his doctorate in physiology at Cambridge and became a lecturer in pharmacology, Dr. Habgood came to feel that something was missing in his scientific training. Science achieved its enormous practical successes, in his view, by narrowing its focus, dealing primarily with things that can be measured or weighed, and excluding human values as much as possible. ''In science, you deliberately cut out all the interesting human things,'' says Dr. Habgood, ''so we are left with this hard, meaningless, valueless universe and we recoil in shock if we think that's all there is.''