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.