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6 similar in shape, pass more quickly through the same space, and in the ratio which the magnitudes have to each other."

What it comes to is this, that if you have a ten-pound weight and a one-pound weight and you drop them together, the ten-pound weight will fall ten times as quickly. The magnitude of the weight settles how quickly it shall fall. That seems to us so astonishing that we can hardly imagine that any one believed it. Yet people went on believing that for 2000 year—just because Aristotle had said it.

Now is it better to believe things people tell you, or is it better to try and find out for yourselves? That is about the hardest question to answer that can be set. At first sight it seems better to believe what people tell you. They may tell you, for instance, that fire burns; and so you need not put your hand in the flame to find out. Or they may tell you that something is poisonous; and if you believe what you are told, you avoid eating it and continue to live. If on the other hand you persist in trying for yourself, you may die; and there is the end of trying things. In this way we seem to have answered our question pretty easily: it seems far better to believe what you are told, because you get all the advantages of other people's experience: and perhaps if they would confine themselves to telling us what they had actually tried, we might be satisfied with this answer.

Unfortunately, however, we cannot always be sure that people are speaking from experience: sometimes we are quite sure that they are not; for instance, we are sure that Aristotle had not tried