Bahá’í Sacred Writings, ‘Abdu’l-Bahá, #315
Every subject presented to a thoughtful audience must be supported by rational proofs and logical arguments. Proofs are of four kinds: first, through sense perception; second, through the reasoning faculty; third, from traditional or scriptural authority; fourth, through the medium of inspiration. That is to say, there are four criteria or standards of judgement by which the human mind reaches its conclusions. We will first consider the criterion of the senses. This is a standard still held to by the materialistic philosophers of the world. They believe that whatever is perceptible to the senses is a verity, a certainty and without doubt existent. For example, they say, “Here is a lamp which you see, and because it is perceptible to the sense of sight, you cannot doubt its existence. There is a tree; your sense of vision assures you of its reality, which is beyond question. This is a man; you see that he is a man; therefore, he exists.” In a word, everything confirmed by the senses is assumed to be as undoubted and unquestioned as the product of five multiplied by five; it cannot be twenty-six nor less than twenty-five. Consequently, the materialistic philosophers consider the criterion of the senses to be first and foremost.
But in the estimation of the divine philosophers this proof and assurance is not reliable; nay, rather, they deem the standard of the senses to be false because it is imperfect. Sight, for instance, is one of the most important of the senses, yet it is subject to many aberrations and inaccuracies.… There are numberless instances of this kind which show the error and inaccuracy of the senses. Therefore, the divine philosophers have considered this standard of judgement to be defective and unreliable.
The second criterion is that of the intellect. The ancient philosophers in particular considered the intellect to be the most important agency of judgement. Among the wise men of Greece, Rome, Persia and Egypt the criterion of true proof was reason. They held that every matter submitted to the reasoning faculty could be proved true or false and must be accepted or rejected accordingly. But in the estimation of the people of insight this criterion is likewise defective and unreliable, for these same philosophers who held to reason or intellect as the standard of human judgement have differed widely among themselves upon every subject of investigation. The statements of the Greek philosophers are contradictory to the conclusions of the Persian sages. Even among the Greek philosophers themselves there is continual variance and lack of agreement upon any given subject. Great difference of thought also prevailed between the wise men of Greece and Rome. Therefore, if the criterion of reason or intellect constituted a correct and infallible standard of judgement, those who tested and applied it should have arrived at the same conclusions. As they differ and are contradictory in conclusions, it is an evidence that the method and standard of test must have been faulty and insufficient.
The third criterion or standard of proof is traditional or scriptural—namely, that every statement or conclusion should be supported by traditions recorded in certain religious books. When we come to consider even the Holy Books—the Books of God—we are led to ask, “Who understands these books? By what authority of explanation may these Books be understood?” It must be the authority of human reason, and if reason or intellect finds itself incapable of explaining certain questions, or if the possessors of intellect contradict each other in the interpretation of traditions, how can such a criterion be relied upon for accurate conclusions?
The fourth standard is that of inspiration. In past centuries many philosophers have claimed illumination or revelation, prefacing their statements by the announcement that “this subject has been revealed through me” or “thus do I speak by inspiration”. Of this class were the philosophers of the Illuminati. Inspirations are the promptings or susceptibilities of the human heart. The promptings of the heart are sometimes satanic. How are we to differentiate them? How are we to tell whether a given statement is an inspiration and prompting of the heart through the merciful assistance or through the satanic agency?
Consequently, it has become evident that the four criteria or standards of judgement by which the human mind reaches its conclusions are faulty and inaccurate. All of them are liable to mistake and error in conclusions. But a statement presented to the mind accompanied by proofs which the senses can perceive to be correct, which the faculty of reason can accept, which is in accord with traditional authority and sanctioned by the promptings of the heart, can be adjudged and relied upon as perfectly correct, for it has been proved and tested by all the standards of judgement and found to be complete. When we apply but one test, there are possibilities of mistake. This is self-evident and manifest.