Presently he said:
“What is a ‘machine’? The word has been variously defined. Here is one definition from a popular dictionary; ‘Any instrument or organization by which power is applied and made effective, or a desired effect produced.’ Well, then, is not a man a machine? And you will admit that he thinks—or thinks he thinks.”
“If you do not wish to answer my question,” I said, rather testily, “why not say so?—all that you say is mere evasion. You know well enough that when I say ‘machine’ I do not mean a man, but something that man has made and controls.”
“When it does not control him,” he said, rising abruptly and looking out of a window, whence nothing was visible in the blackness of a stormy night. A moment later he turned about and with a smile said:
“I beg your pardon; I had no thought of evasion. I considered the dictionary man’s unconscious testimony suggestive and worth something in the discussion. I can give your question a direct answer easily enough; I do believe that a machine thinks about the work that it is doing.”
That was direct enough, certainly. It was not altogether pleasing, for it tended to confirm a sad suspicion that Moxon’s devotion to study and work in his machine-shop had not been good for him. I knew, for one thing, that he suffered from insomnia, and that is no light affliction. Had it affected his mind? His reply to my question seemed to me then evidence that it had; perhaps I should think differently about it now. I was younger then, and among the blessings that are not denied to youth is ignorance. Incited by that great stimulant to controversy, I said:
“And what, pray, does it think with—in the absence of a brain?”
The reply, coming with less than his customary delay, took his favorite form of counter-interrogation:
“With what does a plant think—in the absence of a brain?”
“Ah, plants also belong to the philosopher class! I should be pleased to know some of their conclusions; you may omit the premises.”
“Perhaps,” he replied, apparently unaffected by my foolish irony, “you may be able to infer their convictions from their acts. I will spare you the familiar examples of the sensitive mimosa, the several insectivorous flowers and those whose stamens bend down and shake their pollen upon the entering bee in order that he may fertilize their distant mates. But observe this. In an open spot in my garden I planted a climbing vine. When it was barely above the surface I set a stake into the soil a yard away. The vine at once made for it, but as it was about to reach it after several days I removed it a few feet. The vine at once altered its course, making an acute angle, and again made for the stake. This maneuver was repeated several times, but finally, as if discouraged, the vine abandoned the pursuit and ignoring further attempts to divert it traveled to a small tree, further away, which it climbed.
“Roots of the eucalyptus will prolong themselves incredibly in search of moisture. A well-known horticulturist relates that one entered an old drain pipe and followed it until it came to a break, where a section of the pipe had been removed to make way for a stone wall that had been built across its course. The root left the drain and followed the wall until it found an opening where a stone had fallen out. It crept through and following the other side of the wall back to the drain, entered the unexplored part and resumed its journey.”
“And all this?”
“Can you miss the significance of it? It shows the consciousness of plants. It proves that they think.”
“Even if it did—what then? We were speaking, not of plants, but of machines. They may be composed partly of wood—wood that has no longer vitality—or wholly of metal. Is thought an attribute also of the mineral kingdom?”
“How else do you explain the phenomena, for example, of crystallization?”
“I do not explain them.”
“Because you cannot without affirming what you wish to deny, namely, intelligent cooperation among the constituent elements of the crystals. When soldiers form lines, or hollow squares, you call it reason. When wild geese in flight take the form of a letter V you say instinct. When the homogeneous atoms of a mineral, moving freely in solution, arrange themselves into shapes mathematically perfect, or particles of frozen moisture into the symmetrical and beautiful forms of snowflakes, you have nothing to say. You have not even invented a name to convey your heroic unreason.”
Moxon was speaking with unusual animation and earnestness. As he paused I heard in an adjoining room known to me as his “machine-shop,” which no one but himself was permitted to enter, a singular thumping sound, as of some one pounding upon a table with an open hand. Moxon heard it at the same moment and, visibly agitated, rose and hurriedly passed into the room whence it came. I thought it odd that any one else should be in there, and my interest in my friend—with doubtless a touch of unwarrantable curiosity—led me to listen intently, though, I am happy to say, not at the keyhole. There were confused sounds, as of a struggle or scuffle; the floor shook. I distinctly heard hard breathing and a hoarse whisper which said “Damn you!” Then all was silent, and presently Moxon reappeared and said, with a rather sorry smile:
“Pardon me for leaving you so abruptly. I have a machine in there that lost its temper and cut up rough.”
Fixing my eyes steadily upon his left cheek, which was traversed by four parallel excoriations showing blood, I said:
“How would it do to trim its nails?”
I could have spared myself the jest; he gave it no attention, but seated himself in the chair that he had left and resumed the interrupted monologue as if nothing had occurred:
“Doubtless you do not hold with those (I need not name them to a man of your reading) who have taught that all matter is sentient, that every atom is a living, feeling, conscious being. I do. There is no such thing as dead, inert matter; it is all alive; all instinct with force, actual and potential; all sensitive to the same forces in its environment and susceptible to the contagion of higher and subtler ones residing in such superior organisms as it may be brought into relation with, as those of man when he is fashioning it into an instrument of his will. It absorbs something of his intelligence and purpose—more of them in proportion to the complexity of the resulting machine and that of its work.
“Do you happen to recall Herbert Spencer’s definition of ‘Life’? I read it thirty years ago. He may have altered it afterward, for anything I know, but in all that time I have been unable to think of a single word that could profitably be changed or added or removed. It seems to me not only the best definition, but the only possible one.
” ‘Life,’ he says, ‘is a definite combination of heterogeneous changes, both simultaneous and successive, in correspondence with external coexistences and sequencies.’ ”
“That defines the phenomenon,” I said, “but gives no hint of its cause.”
“That,” he replied, “is all that any definition can do. As Mill points out, we know nothing of cause except as an antecedent—nothing of effect except as a consequent. Of certain phenomena, one never occurs without another, which is dissimilar: the first in point of time we call cause, the second, effect. One who had many times seen a rabbit pursued by a dog, and had never seen rabbits and dogs otherwise, would think the rabbit the cause of the dog.
“But I fear,” he added, laughing naturally enough, “that my rabbit is leading me a long way from the track of my legitimate quarry: I’m indulging in the pleasure of the chase for its own sake. What I want you to observe is that in Herbert Spencer’s definition of ‘life’ the activity of a machine is included—there is nothing in the definition that is not applicable to it. According to this sharpest of observers and deepest of thinkers, if a man during his period of activity is alive, so is a machine when in operation. As an inventor and constructor of machines I know that to be true.”
Moxon was silent for a long time, gazing absently into the fire. It was growing late and I thought it time to be going, but somehow I did not like the notion of leaving him in that isolated house, all alone except for the presence of some person of whose nature my conjectures could go no further than that it was unfriendly, perhaps malign. Leaning toward him and looking earnestly into his eyes while making a motion with my hand through the door of his workshop, I said: