Common Sense, THE PHILOSOPHY OF. There are certain beliefs that have been current among men in all ages, which by some philosophers have been declared to be groundless illusions. Of these, the most remarkable instance is the belief in an external, material world, independent of any mind to perceive it. Berkeley's doctrine (see BERKELEY) seemed to his contemporaries to contradict this belief, and affirm that there is no such thing as a material world; and Hume, carrying the same principles to their full length, disintegrated the world of spirits, and left nothing in nature but isolated ideas and impressions.
A dead-lock in philosophy was the result of these doctrines of Berkeley and Hume; and the solution offered by Reid consisted in setting up common sense as an arbiter from which there could be no appeal—that is to say, the universally admitted impressions of mankind were to be taken as corresponding to the fact of things without any further scrutiny. It is only the same view otherwise expressed, when it is declared by other philosophers that the deliverance of consciousness must be presumed true. According to Sir W. Hamilton, in the most elaborate vindication of the common-sense philosophy that has ever been produced (in his edition of Reid's works), consciousness assures us that, in perception, we are immediately cognisant of an external and extended non-ego (not-self); and that the testimony of consciousness must be viewed as entitled to prompt and unconditional assent.
The conclusiveness of this reasoning is disputed by many, who say that it is an abnegation of the tasks of philosophy, and may establish mere prejudices as dictates of consciousness. Consciousness (q.v.) is a very wide word, comprising indeed everything that we call mind. Suppose, it is argued, we were to maintain that the veracity of each one's memory was beyond all question or dispute, it would be apparent at once how the case really stands. But there must be a standard truth. Experience is the criterion how far the memory is to be trusted; and possibly the same may be true of the larger fact named consciousness. See PHILOSOPHY, PSYCHOLOGY.
The truths of common sense, assumed to be those of consciousness, are such as these: the laws of Identity, Contradiction, and Excluded Middle; the axioms of Mathematics; the law of Causality (see CAUSE); the doctrine of an innate moral sense (see ETHICS); the doctrine of man's Moral Liberty (see WILL); the existence of an external world independent of every perceptive mind. Some of these truths, which however by no means stand all on the same footing, are termed Intuitions, Intuitive Cognitions, Instincts, Feelings, Beliefs, Principles, Ultimate or Primordial Elements, Truths a priori. Kant's mission was to investigate the origin of such of those truths as might be accounted a priori; see KANT, A PRIORI. The philosophy of common sense, as promulgated by Reid, bore reference especially to the denial by Berkeley of the received view of the material world. See SCOTTISH PHILOSOPHY, RELATIVITY OF KNOWLEDGE.