"What is it?--" "'Tis impossible the same thing should be, and not be at the same time," are maxims of such universal usefulness, that without them we could neither _judge, discourse,_ nor _act_. These principles may not always make their appearance in formal propositions, but still they guide all our thoughts in the same manner as when a musician plays a careless voluntary upon a harpsichord--he is guided by rules of music he long since became familiar with, though now scarcely sensible of them. 'A butcher loses his knife, and looks all about for it, and remarks as the motive of his search, "I am sure it must be somewhere or other." By which rude saying it is evident he is guided by the axiom last mentioned. Had he not the knowledge of this axiom beforehand, did he think it possible that his knife could be _no where_ or in _no place_ he would never take pains to look for it. We may observe many such axioms as this guiding the actions of the vulgar, and it is no unworthy speculation to observe their behaviour and words, which proceed from uncorrupted nature, and retrieve the axioms from which their conduct proceeds.'* * Solid Philosophy, asserted against the Fancies of the Idealists. (Locke's Understanding is the work controverted.) By J. S.. London, 1679. The outlines of the science of morality are thus comprehensively sketched by Sir James Mackintosh: the origin, value, and application of first principles are indicated with his usual felicity. 'The usages and laws of nations, the events of history, the opinions of philosophers, the sentiments of orators and poets, as well as the observations of common life, are in truth, the materials out of which the science of morality to formed; and those who neglect them are justly chargeable with a vain attempt to philosophise without regard to fact and experienee--the sole foundation of all true philosophy. The natural order undoubtedly dictates that we should first search for the _original principles_ of the science in human nature; then apply them to the regulation of the conduct of individuals, and lastly employ them for the decision of those difficult and complicated questions that arise with respect to the intercourse of nations.' To search for ultimate principles is to discover at a glance the whole bearings of a great question. Through what clouds of politics had the historian of Rome penetrated when he announced that the principles of a free constitution are irrecoverably lost when the legislative power is nominated by the executive.