rational order. Much of this defence revolved around arguments such as the infinite monkey metaphor. Democritus had already apparently used such arguments at the time of Socrates, saying that there will be infinite planets, and only some having an order like the planet we know. But the Epicureans refined this argument, by proposing that the actual number of types of atoms in nature is small, not infinite, making it less coincidental that after a long period of time, certain orderly outcomes will result. These were not the only positions held in classical times. A more complex position also continued to be held by some schools, such as the Neoplatonists, who, like Plato and Aristotle, insisted that Nature did indeed have a rational order, but were concerned about how to describe the way in which this rational order is caused. According to Plotinus for example, Plato's metaphor of a craftsman should be seen only as a metaphor, and Plato should be understood as agreeing with Aristotle that the rational order in nature works through a form of causation unlike everyday causation. In fact, according to this proposal each thing already has its own nature, fitting into a rational order, whereby the thing itself is "in need of, and directed towards, what is higher or better". David Hume Louis Loeb writes that David Hume, in his Enquiry, "insists that inductive inference cannot justify belief in extended objects". Loeb also quotes Hume as writing: Loeb notes that "we observe neither God nor other universes, and hence no conjunction involving them. There is no observed conjunction to ground an inference either to extended objects or to God, as unobserved causes." Hume also presented a criticism of the argument in his Dialogues Concerning Natural Religion. The character Philo, a religious sceptic, voices Hume's criticisms of the argument. He argues that the design argument is built upon a faulty analogy as, unlike with man-made objects, we have not witnessed the design of a universe, so do not know whether the universe was the result of design. Moreover, the size of the universe makes the analogy problematic: although our experience of the universe is of order, there may be chaos in other parts of the universe. Philo argues: Philo also proposes that the order in nature may be due to nature alone. If nature contains a principle of order within it, the need for a designer is