A cryptologist then delivered a long rambling account of the patterns of character groupings that occurred in Charlie’s personal documents. They had already completed preliminary processing of all the individual papers, the contents of the wallet, and one of the books; they were about half way through the second. There were many tables, but nobody knew yet what they meant; some structured lines of symbols suggested mathematical formulas; certain page and section headings matched entries in the text. Some character strings appeared with high frequency, some with less; some were concentrated on a few pages, while others were evenly spread throughout. There were lots of figures and statistics. Despite the enthusiasm of the speaker, the mood of the room grew heavy and the questions fewer. They knew he was a bright guy; they wished he’d stop telling them.

At length, Danchekker, who had been noticeably silent through most of the proceedings and appeared to be growing increasingly impatient as they continued, obtained leave from the chair to address the meeting. He rose to his feet, clasped his lapels, and cleared his throat. "We have devoted as much time as can be excused to exploring improbable and far-flung suggestions which, as we have seen, turn out to be fallacious." He spoke confidently, taking in the length of the table with side-to-side swings of his body. "The time has surely come, gentlemen, for us to dally no longer, but to concentrate our efforts on what must be the only viable line of reasoning open to us. I state, quite categorically, that the race of beings to whom we have come to refer as the Lunarians originated here, on Earth, as did the rest of us. Forget all your fantasies of visitors from other worlds, interstellar travelers, and the like. The Lunarians were simply products of a civilization that developed here on our own planet and died out for reasons we have yet to determine. What, after all, is so strange about that? Civilizations have grown and passed away in the brief span of our more orthodox history, and no doubt others will continue the pattern. This conclusion follows from comprehensive and consistent evidence and from the proven principles of the various natural sciences. It requires no invention, fabrication, or supposition, but derives directly from unquestionable facts and the straightforward application of established methods of inference!" He paused and cast his eyes around the table to invite comment.

Nobody commented. They already knew his arguments. Danchekker, however, seemed about to go through it all again. Evidently he had concluded that attempts to make them see the obvious by appealing to their powers of reason alone were not enough; his only resort then was insistent repetition until they either concurred or went insane.

Hunt leaned back in his chair, took a cigarette from a box lying nearby on the table, and tossed his pen down on his pad. He still had reservations about the professor’s dogmatic attitude, but at the same time he was aware that Danchekker’s record of academic distinction was matched by those of few people alive at the time. Besides, this wasn’t Hunt’s field. His main objection was something else, a truth he accepted for what it was and made no attempt to fool himself by rationalizing: Everything about Danchekker irritated him. Danchekker was too thin; his clothes were too old-fashioned-he carried them as if they had been hung on to dry. His anachronistic gold-rimmed spectacles were ridiculous. His speech was too formal. He had probably never laughed in his life. A skull vacuum-packed in skin, Hunt thought to himself.

"Allow me to recapitulate," Danchekker continued. "Homo sapiens-modern man-belongs to the phylum Vertebrata. So, also, do all the mammals, fish, birds, amphibians, and reptiles that have ever walked, crawled, flown, slithered, or swum in every corner of the Earth. All vertebrates share a common pattern of basic architecture, which has remained unchanged over millions of years despite the superficial, specialized adaptations that on first consideration might seem to divide the countless species we see around us.

"The basic vertebrate pattern is as follows: an internal skeleton of bone or cartilage and a vertebral column. The vertebrate has two pairs of appendages, which may be highly developed or degenerate, likewise a tail. It has a centrally located heart, divided into two or more chambers, and a closed circulatory system of blood made up of red cells containing hemoglobin. It has a dorsal nerve cord which bulges at one end into a five-part brain contained in a head. It also has a body cavity that contains most of its vital organs and its digestive system. All vertebrates conform to these rules and are thereby related."

The professor paused and looked around as if the conclusion were too obvious to require summarizing. "In other words, Charlie’s whole structure shows him to be directly related to a million and one terrestrial animal species, extinct, alive, or yet to come. Furthermore, all terrestrial vertebrates, including ourselves and Charlie, can be traced back through an unbroken succession of intermediate fossils as having inherited their common pattern from the earliest recorded ancestors of the vertebrate line"-Danchekker’s voice rose to a crescendo-"from the first boned fish that appeared in the oceans of the Devonian period of the Paleozoic era, over four hundred million years ago!" He paused for this last to take hold and then continued. "Charlie is as human as you or I in every respect. Can there be any doubt, then, that he shares our vertebrate heritage and therefore our ancestry? And if he shares our ancestry, then there is no doubt that he also shares our place of origin. Charlie is a native of planet Earth."

Danchekker sat down and poured himself a glass of water. A hubbub of mixed murmurings and mutterings ensued, punctuated by the rustling of papers and the clink of water glasses. Here and there, chairs creaked as cramped limbs eased themselves into more comfortable positions. A metallurgist at one end of the table was gesturing to the man seated next to her. The man shrugged, showed his empty palms, and nodded his head in Danchekker’s direction. She turned and called to the professor. "Professor Danchekker… Professor…" Her voice made itself heard. The background noise died away. Danchekker looked up. "We’ve been having a little argument here-maybe you’d like to comment Why couldn’t Charlie have come from a parallel line of evolution somewhere else?"

"I was wondering that, too," came another voice. Danchekker frowned for a moment before replying.

"No. The point you are overlooking here, I think, is that the evolutionary process is fundamentally made up of random events. Every living organism that exists today is the product of a chain of successive mutations that has continued over millions of years. The most important fact to grasp is that each discrete mutation is in itself a purely random event, brought about by aberrations in genetic coding and the mixing of the sex cells from different parents. The environment into which the mutant is born dictates whether it will survive to reproduce its kind or whether it will die out. Thus, some new characteristics are selected for further miprovement, while others are promptly eradicated and still others are diluted away by interbreeding.

"There are still people who find this principle difficult to accept-primarily, I suspect, because they are incapable of visualizing the implications of numbers and time scales beyond the ranges that occur in everyday life. Remember we are talking about billions of billions of combinations coming together over millions of years.

"A game of chess begins with only twenty playable moves to choose from. At every move the choice available to the player is restricted, and yet, the number of legitimate positions that the board could assume after only ten moves is astronomical. Imagine, then, the number of permutations that could arise when the game continues for a billion moves and at each move the player has a billion choices open to him. This is the game of evolution. To suppose that two such independent sequences could result in end products that are identical would surely be demanding too much of our credulity. The laws of chance and statistics are quite firm when applied to sufficiently large numbers of samples. The laws of thermodynamics, for example, are nothing more than expressions of the probable behavior of gas molecules, yet the numbers involved are so large that we feel quite safe in accepting the postulates as rigid rules; no significant departure from them has ever been observed. The probability of the parallel line of evolution that you suggest is less than the probability of heat flowing from the kettle to the fire, or of all the air molecules in this room crowding into one corner at the same time, causing us all to explode spontaneously. Mathematically speaking, yes-the possibility of parallelism is finite, but so indescribably remote that we need consider it no further."