New York — The greatest danger to the economy isn't so much inflation or trade imbalances as it is a loss of faith, says Dr. Peter Schwartz, a futurist for SRI International in California. In Quest-80 magazine he says the Great Depression was "a psychological state," and asks, "Have you ever wondered why, when all the machines and factories and workers and consumers were still There, the economy collapsed between 1929 and 1933? . . . My understanding is that it basically resulted from people withdrawing their belief in the system. They decided it wasn't working anymore, then they behaved as if it wasn't working anymore, and lo and behold, it stopped working."