But though this may be true enough in practice, it scarcely clears up the position of logic in human affairs. Logic is a machine of the mind, and if it is used honestly it ought to bring out an honest conclusion. When people say that you can prove anything by logic, they are not using words in a fair sense. What they mean is that you can prove anything by bad logic. Deep in the mystic ingratitude of the soul of man there is an extraordinary tendency to use the name for an organ, when what is meant is the abuse or decay of that organ. Thus we speak of a man suffering from 'nerves,' which is about as sensible as talking about a man suffering from ten fingers. We speak of 'liver' and 'digestion' when we mean the failure of liver and the absence of digestion. And
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