This principle is always assumed in all practical affairs. If a man were to send a cargo abroad without _any_ evidence that it was wanted, he would be called a fool; and so in all other concerns, every sane man takes this for his rule of conduct. The preceding include the principles which it is believed are the grand foundation on which rest most of the practical knowledge of life, as well as the doctrines and duties both of natural and revealed religion. There are some other intuitive truths which are not introduced here, and there are some principles that others have placed in this honorable position which could not stand the _test_ here introduced, and claimed to be the only true and reliable one. The intuitive truths have been called "fundamental truths," because they are the ultimate basis of all knowledge secured or established by the process of _reasoning_. This process consists in assuming a certain proposition to be true as the _basis_ of an argument. If this proposition is granted, or supposed to be granted, then the reasoner proceeds to show that the point in dispute is in reality _included_ in the truth already granted, so that believing the first proposition, or basis, necessarily involves a belief in the one to be proved. For example, if a man wishes to prove that a certain person is a benevolent man, he proceeds thus: Let it be granted that all persons who are habitually contriving and laboring to promote the happiness of all around them are benevolent persons. This basis proposition being conceded to be true, the reasoner proceeds to present evidence that the person in question habitually is laboring for the good of others. This being done, he draws the conclusion that this person is _included_ in the class which have been granted to be benevolent. _Reasoning_, then, is a process for exhibiting evidence that a point which is disputed is included in a proposition already believed and allowed. But suppose the disputant denies the truth of the basis or foundation proposition, then it becomes necessary to establish that proposition by another act of reasoning. In order to do this, still another proposition is assumed which is allowed to be true, and which the reasoner then attempts to show includes his former basis proposition. This process may thus be continued till, finally, it comes to pass that the basis proposition assumed is an intuitive truth. In this case the victory is secure; for whatever can be shown to be embraced in an intuitive truth must be conceded to be true, and whatever is contradictory to an intuitive truth must be allowed to be false. Now it can be shown that all the reliable practical knowledge of this life can be thus traced back till it is seen to rest on some intuitive truth as its basis.