"I meant theoretically," Burris said.
"Theoretically—" Dr. O'Connor began, and smiled again—"Theoretically, if your mind were being read, this machine would detect it, supposing that the machine were in operating condition and all of the other qualifications had been met. You see, Mr. Burris, no matter how poor a telepath a man may be, he has some slight ability—even if only very slight—to detect the fact that his mind is being read."
"You mean, if somebody was reading my mind, I'd know it?" Burris said. His face showed, Malone realized, that he plainly disbelieved this statement.
"You would know it," Dr. O'Connor said, "but you would never know you knew it. To elucidate: in a normal person—like you, for instance, or even like myself—the state of having one's mind read merely results in a vague, almost sub-conscious feeling of irritation, something that could easily be attributed to minor worries, or fluctuations in one's hormonal balance. The hormonal balance, Mr. Burris, is—"
"Thank you," Burris said with a trace of irritation. "I know what hormones are."
"Ah. Good," Dr. O'Connor said equably. "In any case, to continue: this machine interprets those specific feelings as indications that the mind is being—ah—'eavesdropped' upon."
You could almost see the quotation marks around what Dr. O'Connor considered slang dropping into place, Malone thought.
"I see," Burris said with a disappointed air. "But what do you mean, it won't detect a telepath? Have you ever actually worked with a telepath?"
"Certainly we have," Dr. O'Connor said. "If we hadn't, how would we be able to tell that the machine was, in fact, indicating the presence of telepathy? The theoretical state of the art is not, at present, sufficiently developed to enable us to—"
"I see," Burris said hurriedly. "Only wait a minute."