In any case there is an intense modern interest in machines that imitate life. The great difference between magic and the scientific imitation of life is that where the former is content to copy external appearance, the latter is concerned more with performance and behavior.
[Walter even gave the tortoises a mock-biological name, Machina speculatrix] because they illustrate particularly the exploratory, speculative behaviour that is so characteristic of most animals.
[E]xperiments with a simple little machine, designed to mimic certain elementary features of animal behavior... Consisting only of two vacuum tubes, two motors, a photoelectric cell and a touch contact, all enclosed in a tortoise-shaped 'shell, the model was a species of artificial creature which could explore its surroundings and seek out favorable conditions. It was named Machine speculatrix.
The mechanism of learning is of course one of the most enthralling and baffling mysteries in the field of biology.
These models are of course so simple that any more detailed comparison between them and living creatures would be purely conjectural.
[A]n electro-mechanical creature which behaves so much like an animal that it has been known to drive a not usually timid lady upstairs to lock herself in her bedroom, an interesting blend of magic and science.
Not in looks, but in action, the model must resemble an animal. Therefore it must have these or some measure of these attributes: exploration, curiosity, free-will in the sense of unpredictability, goalseeking, self-regulation, avoidance of dilemmas, foresight, memory, learning, forgetting, association of ideas, form recognition, and the elements of social accommodation. Such is life.
Some of these patterns of performance were calculable, though only as types of behaviour, in advance; some were quite unforeseen.
Simon, always a fool for simplicity, accepted. Punch took an envelope out of his pocket and scribbled on the back of it. He said, 'This has a simple arithmetical proof but no rational explanation of the paradox.' He gave it to Simon. Simon read it, looked at Punch with raised eyebrows, hunched his shoulders, shook his head sadly, and got up and left the room without a word.