(8) To demand greater exactness in the estimate of causes or effects than a given subject admits of.  In the more complex sciences, Biology, Psychology, Sociology, it is often impossible to be confident that all the conditions of a given phenomenon have been assigned, or that all its consequences have been traced.  The causes of the origin of species and of the great French Revolution have been carefully investigated, and still we may doubt whether they have all been discovered, or whether their comparative importance has been rightly determined; but it would be very unreasonable to treat those things as miraculous and unintelligible.  We read in the Ethics, that a properly cultivated mind knows what degree of precision is to be expected in each science.  The greatest possible precision is always to be sought; but what is possible depends partly on the nature of the study and partly upon the state of scientific preparation.

(9) To treat an agent or condition remote in time as an unconditional cause:  for every moment of time gives an opportunity for new combinations of forces and, therefore, for modifications of the effect.  Thus, although we often say that Napoleon’s Russian expedition was the cause of his downfall, yet the effect was subject to numerous further conditions.  Had the natives not burnt Moscow, had the winter been exceptionally mild, had the Prussians and Austrians not risen against him, the event might have been very different.  It is rash to trace the liberties of modern Europe to the battle of Marathon.  Indeed, our powers of perception are so unequal to the subtlety of nature, that even in experimental science there is time for molecular changes to occur between what we treat as a cause and the effect as we perceive it; and, in such cases, the strictly unconditional cause has not been discovered.

(10) To neglect the negative conditions to which a cause is subject.  When we say that water boils at 212 deg.  F., we mean “provided the pressure be the same as that of the atmosphere at about the sea-level”; for under a greater pressure water will not boil at that temperature, whilst under less pressure it boils at a lower temperature.  In the usual statement of a law of causation, ‘disturbing,’ ‘frustrating,’ ‘counteracting’ circumstances (that is, negative conditions) are supposed to be absent; so that the strict statement of such a law, whether for a remote cause, or for an immediate cause (when only positive conditions are included), is that the agent or assemblage of conditions, tends to produce such an effect, other conditions being favourable, or in the absence of contrary forces.

(11) It is needless to repeat what has already been said of other fallacies that beset inductive proof; such as the neglect of a possible plurality of causes where the effect has been vaguely conceived; the extension of empirical laws beyond adjacent cases; the chief errors to which the estimate of analogies and probabilities, or the application of the principles of classification are liable; and the reliance upon direct Induction where the aid of Deduction may be obtained, or upon observation where experiment may be employed.  As to formal fallacies that may be avoided by adhering to the rules of logical method, this may suffice.