sounds pretty
plausible."

Dalgetty shook his head. "Suppose I were an engineer," he said, "and
suppose I saw an avalanche coming down on me. I might know exactly
what to do to stop it--where to plant my dynamite, where to build my
concrete wall and so on. Only the knowledge wouldn't help me. I'd have
neither the time nor the strength to use it.

"The situation is similar with regard to human dynamics, both mass and
individual. It takes months or years to change a man's convictions and
when you have hundreds of millions of men...." He shrugged. "Social
currents are too large for all but the slightest, most gradual
control. In fact perhaps the most valuable results obtained to date
are not those which show what can be done but what cannot."

"You speak with the voice of authority," said the man.

"I'm a psychologist," said Dalgetty truthfully enough. He didn't add
that he was also a subject, observer and guinea pig in one. "And I'm
afraid I talk too much. Go from bad to voice."

"Ouch," said the man. He leaned his back against the rail and his
shadowy hand extended a pack. "Smoke?"

"No, thanks, I don't."

"You're a rarity." The brief lighter-flare etched the stranger's face
against the dusk.

"I've found other ways of relaxing."

"Good for you. By the way I'm a professor myself. English Litt at
Colorado."

"Afraid I'm rather a roughneck in that respect," said Dalgetty. For a
moment he had a sense of loss. His thought processes had become too
far removed from the ordinary human for him to find much in fiction or
poetry. But music, sculpture, painting--there was something else. He
looked over the broad glimmering water, at the stations dark against
the first stars, and savored the many symmetries and harmonies with a
real pleasure. You needed senses like his before you could know what a
lovely world this was.

"I'm on vacation now," said the man. Dalgetty did not reply in kind.
After a moment--"You are too, I suppose?"

Dalgetty felt a slight shock. A personal question from a
stranger--well, you didn't expect otherwise from someone like the girl
Glenna but a professor should be better conditioned to privacy
customs.

"Yes," he said shortly. "Just visiting."

"By the way, my name is Tyler, Harmon Tyler."

"Joe Thomson." Dalgetty shook hands with him.

"We might continue our conversation if you're going to be around for
awhile," said Tyler. "You raised some interesting points."

Dalgetty considered.