As they flash slides of global perspectives on their living-room screen, the Kurtzes describe the grand strategic thinking to support their proposition. It starts with feudal castles in Europe. Pictures of ruined castles flash on the screen.

Howard: "For centuries men sought security behind the walls of castles."

Harriet: "The larger the castle, the greater the sense of security. Then technology produced gunpowder-in-cannon. The castle became indefensible. An historic era began to collapse."

Howard (flashing a cartoon of a cracked castle): "If the Lord of a castle was a dove and turned weak in the face of his enemies, he and his people were defeated."

Harriet: "On the other hand, if the Lord of a castle was a hawk, he and his enemies shot more and more holes in each other's castles. In time the ruins of castles all across the landscape signaled the final collapse of the old security systems."

As the Kurtzes recount it, security defined by castle domains was replaced (after centuries of bloodshed) by the modern nation-state with its own defensible borders. Modern technology has spent most of the 20th Century attempting to break down the national defensive boundaries.It has at least succeeded.

Harriet: "The nation-state is becoming indefensible. A historic era is collapsing all around the world. Both sides of a nucler war may be obliterated. Our strategic weapons are becoming suicidal weapons. We will find new ideas or risk mutual destruction."

Howard: "The problem we face today may be simply stated: we will now develop global systems and institutions to assure the security and well-being of all nations - or no nation will ever find security again."

BETWEEN the preacher wife and the engineer husband, the basic technique of "War Control Planners Inc." is to take the latest marvels of war-and-space technology and try to image how this same hardware might be used to assist in global peace-keeping.

Back in 1961, for example, the Kurtzes sent a far-out package to the new President, proposing an "all-nation declaration of independence" and suggesting how the begin to understand that the Defense Department can no longer defend us.

"Conceptually," Howard says, "the Joint Chiefs are now working on a Kamikaze strategy, threating to destroy ourselves by throwing more and more of our fire-power at the enemy."

"The only reason the concept hasn't changed," adds Harriet, "is that strategy usually changes in the ashes of defeat and we haven't had this defeat. We can't have it."

This future of "war safety" which the Kurtzes envision would actually entail a whole new future for the American military, once the generals begin to see national security differently. In the meantime, the government is spending about $225 million of peaceful applications of space satellites and about 10 times that amount on secret military uses.

THE ARMAMENTS continue to build up, the arms treaties notwithstanding, but somehow the Kurtzes are not discouraged. They report that dozens of people inside the government agencies discreetly encourage their crusade, offering better space photos for the slide-show, correcting their technical mistakes, sharing this idea that a "global information cooperative" is a genuine route to a peaceful world.

President Carter's new director of the White House Office of Science and Technology, Frank Press, recently sent them a cordial response, assuring them that scientists generally share their broad goals and urging them to be patient with the constraints of experimentation.

"As is often the case, political and social progress lags behind technological possibilities and sometimes prevent us from moving as rapid as we might wish in these areas," Press wrote . . . The global satellite system which you have so eloquantly pleaded for is in fact evolving, but it cannot be created full-blown overnight."

Sometimes, Howard says, "we feel like the people who spent years building a boat in the basement, only to find there was no door big enough to let it out."

Harriet says: "If we have a contribution to make, it's likely to be a very small but a very crucial one. That's what we tell ourselves when we're trying to keep afloat. I don't know whether that's right or not."

And, now, patient readers, armed with the hope of the Kurtzes, you may return to reading about the arms race.