Hallucinations are possible, and in the more abstract domains of mental activity errors are possible also; and will be ever more frequent. Nevertheless the reality of outside facts in the sense stated above can as little be doubted as the reality of immediate perception; and all the facts established by science, if they are but true, are as much realities as is the resistance of the table to the pressure of my hand or the perception of the sheet of paper by my eye.
#Inferential facts, if true, are real.#
Facts established by science are those observations which are made with all the necessary exactness as well as completeness from certain groups of experiences, and formulated with precision. The theory of atoms, for instance, is true in so far as all elements combine in certain proportions, which shows that the ultimate particles of which the elements consist are of a definite mass. Atoms, if the word is understood in this sense, are realities. The theory of atoms, however, is not proved in the sense that atoms are ἄτομοι; or single, isolated, minute bodies of a peculiar individuality—separate, indivisible, and eternal entities. Whether they are concrete things or certain forms of motion in a continuous substance, whether they are vortices or whirls of a certain density and velocity in an ether ocean, or whatever else be their character, is not yet known. If we exclude from the concept "atoms" all hypothetical views and confine their meaning strictly to the formulation of certain experiences, we have to deal with facts that are real. Theories are true in so far as they comprehend in a formula a certain group of facts, and a hypothesis becomes reliable to the extent that it agrees with facts. The slightest actual disagreement with facts is sufficient to overthrow the most ingenious hypothesis.
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This leads us to the question, What is meant by true? What is truth?
#Facts and reality. Truth and mind.#
The epitheton "true" has reference to representative states only. A representation is true, if it conforms to, or agrees with, experience; in other words, if it is an interpretation of given facts, is free from contradiction, and nowhere collides with any one of the given facts and their consistent interpretation. There is no sense in speaking of mere feelings as being true. We can never meet, in our own experience, with given facts that are nothing but meaningless feelings; for we (as thinking beings) are incapable of bringing meaningless feelings into the scope of consciousness, since in the very act of thinking we comment upon the given facts of our feelings. But supposing there are mere given facts, mere meaningless feelings void of any representative element, the application of the word true to such non-representative feelings would be improper. States of consciousness become true or untrue only by being representative of objective conditions or things. There is no trace of truth in mere feelings, but only in representative feelings. Truth and error are the privilege of mind. A representation is true, if all the various experiences concerning a certain thing or state of things agree with the representation; it is untrue if they do not agree.
We observe that certain classes of facts, in spite of all variety, exhibit in one or another respect a sameness, and science attempts to express the sameness in exact formulas. These formulas we call natural laws. If a natural law covers all cases of a class that have come or even that possibly can come within the range of our experience, if it agrees with every one of them, we call it a truth.
"Truth" accordingly is not at all identical with "fact." These two words are often used as synonyms, but properly employed they are quite distinct. Truth is the agreement of a representation with the facts represented. The fall of a stone is a fact; it is an inferred fact deduced from certain sense-impressions. In so far as the inference is made with necessity as the only proper and simplest explanation of a certain given fact or sense-impression, it must be considered as a fact or as real. The law of gravitation, however, is not a fact, but a truth.
Facts are real. There is no sense in speaking of facts as being true. Representations of facts are true or untrue. Reality is the characteristic feature of all facts, but truth is a quality that can reside in mind alone.