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which would be so explained if the case had not been prejudged — prejudiced — by the desires. The caution needed here is that in estimating an argument the prejudices of the writer or speaker be taken into account; and that, in making an argument, those assumptions which prejudice intrudes be excluded. The remedy for this fallacy is to love truth more and victory less. The man who wishes to be really, not apparently, successful in debate must come to the question with an earnest desire to find the real relation of cause and effect involved, solely for the sake of the truth. A debating club in which a question is discussed for the sake of victory is not conducive to that attitude of mind necessary to effective argument. The hypocrisy of the judgment in its pretense of reasons blinds to the real reasons when engaged in an actual contest for truth. Much of the so-called drill in debating is only a drill in fluency of words and deftness in manipulating fallacies.
A Posteriori Arguments. — These are arguments from effect to cause, explaining why something is or why something has happened. The effect is known, and the cause which produced it is sought. In the a priori arguments known causes point to unknown future events or to some known effect which the known cause explains; while in the a posteriori arguments the effect is known and the cause sought.
Inference of cause from effect is based on the different thought relations involved in thinking. The whole may be inferred from the part; the substance from the attribute, or the attribute from the substance; from
likenesses, other likenesses, or from differences, other differences; from effect, its adequate cause; from adaptation may be inferred purpose. From the presence of the whole of a steam engine certain parts may be safely inferred; or with a part of it present, the whole will be suggested. The attribute yellow being present in a distant field, some substance, as wheat or clay, will be suggested; and the substance, wheatfield, will suggest some accompanying attribute. Likeness in color, form, texture, and parts of two kinds of fruits will suggest likeness as to flavor and odor; and differences in the first respect named will suggest differences in the second. From the moving train, the steam as an adequate cause of the motion may be inferred. From the adaptation of an anchor to grapple in the bed of the ocean, the inference is readily made that some one designed it. But in all these cases the inference is based on the relation of cause and effect. The adaptation in the anchor is caused by its purpose; that in the nature of the fruits which caused them to be alike in certain respects will cause them to be alike in other respects; that which usually conditions or causes the presence of the yellow color under the conditions observed is still the cause; and whatever there is in the nature of the engine to necessitate the relation of whole and part is permanent in causing that relation.
The so-called signs and resemblances, so often spoken of in argumentation, are only other names for effects. The tolling of a bell is a sign that some one has died; but it is a sign of this because it is an effect
resulting from death. A weapon in possession of the accused man is a sign that he is a murderer; but it is a sign because the carrying of such a weapon is an effect produced by the intention of killing some one. The bridge is a sign that men have labored, for it is an effect produced by such a cause. Two objects resemble each other in certain respects, and reasoning by resemblance, some unknown attribute of the one will be like some known attribute of the other. Yet this is reasoning from a known effect to a cause, for it is a belief that whatever caused the similarity in the points observed will cause it in the point with reference to which the inference is made. Signs and points of resemblance are always effects of which the cause is to be inferred.
Laws of Inference from Effect. — The degree of force in the a posteriori argument varies with the certainty of the causal relation on which the inference is based. This depends on (1) the number and complexity of the causes which may produce the effect, and (2) the efficiency and reality of the cause.
1. A cause may be inferred from an effect with certainty when the effect is such that only one cause can produce it. We may argue conclusively that the oak is produced from an acorn; that steam is caused by heat; that the burned house has been on fire; there being no other cause for each phenomenon. The train is moving, and steam may be inferred as the cause; but not conclusively, for there may be other forces moving it, as men, horses, electricity, gravity, etc. When there are many causes, either of which or a combination of which may produce the effect, the inference becomes less certain as the number and complexity increase. As a rule, the number and complexity of causes increase in passing from the physical to the spiritual world. Especially is it difficult to assign causes to social phenomena, so manifold and subtile are the moving forces. And nowhere are fallacies more common.
2. In an argument from resemblance a cause may be inferred with certainty when the resemblances are essential. On the ground that Caesar was selfish and a tyrant, it might safely be inferred that another ruler who was selfish was also a tyrant, there being a causal relation between selfishness and tyranny. Glass is transparent and brittle; but it does not follow that because water is transparent it is also brittle, there being no essential relation between transparency and brittleness. In such cases the burden of proof consists in showing that the points of resemblance are so related to the nature of the object that they are constant marks of it. This may be done by establishing directly a causal relation, as in the case of selfishness and tyranny; or by an accumulation of examples till the uniformity establishes a belief in a constant cause.
Attributes and objects are so often accidental accompaniments of each other without causal relation that arguments from example are fruitful sources of fallacies. The immature and the untrained mind, in their tendency to hasty conclusions, generally infer a causal relation where there is only an accidental coexistence; as, —
Some intemperate man lives to a great age; therefore, intemperance is conducive to longevity. It rained on Monday and the two succeeding days of the week; therefore, when it rains on Monday it will rain three days in the week. A great man smokes; therefore, smoking is manly. Byron was licentious and a great poet; therefore, licentiousness is favorable to poetic inspiration. A man who believes the doctrines of a certain church is immoral; therefore, the doctrines of that church tend to produce immorality.
This kind of argument is much used by the sophist. The demagogue finds it an effective means of carrying conviction to the minds of unthinking people. By means of it, he accounts for the dull or the flourishing condition of the times; the high or the low price of crops and merchandise; the scarcity or the abundance of productions; the demand for labor or the difficulty with which it is obtained; and gives the credit or the blame, as suits his purpose, to the party in power, when the coexistence of the facts may be purely accidental. To prove the value of a classical over a scientific education, or vice versa, some eminent scholar is instanced who has pursued one of these courses; while his eminence may be accounted for by a large number of causes; as, natural endowment, more thorough discipline on account of superior teachers, social opportunities, combined effect of various studies, etc. The proof would be absolutely convincing if the same person could be the subject of each course, for then the conditions would be identical; or, if many examples under similar conditions from each course could be