Here A = skill to make locks implying skill to pick them + the

will to pick them (d1).

B=skill to make locks implying skill to pick them+a will about whose tendencies, one way or the other, nothing is known (δ1).

The argument is that, as A actually picks locks, therefore B does too; and the question is whether the argument is sound.

Now P, the addiction to robbery, is rooted in d1, A's will to pick locks. Hence, as d1 is not known to be a characteristic of B, there is no ground for connecting P with B.

Therefore the analogy is unsound.

So long as an analogical conclusion is not verified it cannot be called true. But, it may be urged, an Unsound Analogy may surely in the strictest sense be false in the case, namely, in which P can be proved on the given data to be incompatible with certain differences, δι, δε, δ3, possessed by B but not by A. In this case is not the argument from Analogy strictly disproved? Certainly; but the disproof would entail a Scientific Induction. It is as difficult to prove such incompatibility as it is to prove or disprove a causal connexion.

Thus, 'Is human life incompatible with absence of water?' To answer this question satisfactorily we must analyse out the properties of Water (considered as a solvent, etc.); we must physiologically analyse the meaning of thirst, and the necessity of a supply of liquid; we must consider in detail the whole question of possible substitutes for water. Not till these processes of analysis are completed can we venture on a downright use of the term 'incompatible.'

Incompatibility would thus seem not to be a matter that concerns Analogy. Analogy deals with points of difference, certainly, as with points of resemblance. But so soon as we can deepen the fact of difference into the fact of incompatibility, we seem almost as certainly to have gone beyond Analogy as we have when we have deepened the fact of resemblance into a fact of causal connexion.

XIII.

THE GOAL OF INDUCTION: CAUSAL EXPLANATION.

(i.) Cause and Causal Law (ch. xliii.).

(ii.) The Process of Scientific Observation (ch. xliv.).

(iii.) The Method of Causal Explanation (ch. xlv.).

Illustrations of the Application of Inductive Method (ch. xlvi.).

CHAPTER XLIII.

XIII. (i.) CAUSE AND CAUSAL LAW.

We have now to consider the form which Induction takes when it most adequately embodies the true interest and intention of Science. Fact, for Science, as we have seen, means Fact in the light of Law ; but for Scientific Induction in particular Fact means 'Effect'Effect that evidences the presence of Cause acting according to uniform Law. Conceived in an explanatory relation to effects, a law is known as a causal law or a law of causation.

The Meaning of the Term 'Law.'

Scientific Laws take shape and develop under the inspiration of the Inductive Principle of Fidelity to Relevant Fact-i.e., to Fact in so far as it answers to the demand of the Inductive Postulate of Uniformity or Determinism (vide Chapter XLVII.). Within the limits of this postulate Fact is supreme. It is Fact that controls the tentative gropings of Hypothesis, and, in proportion as the latter conforms to its requirements, allows it to assume the status of Law. Scientific Laws are laws on sufferance, and they hold their office as interpreters of the world of real fact only so long as there are no other promising hypotheses to perform that function better.

This subordinate position of Law in Science is no exception to the general rule. Law, when healthily operative, is everywhere subordinate, be it to the constitutional authority of a nation's will, to the Principles of Reason and Conscience, or to the requirements of Relevant Fact. It is only the dead law of the Medes and Persians which altereth not.

When, in Science, we speak of a causal law, we in no way conceive it as causing or bringing about effects. The cause which is responsible for the effects is not itself the law through which those effects are interpreted. The law is a tentative, though approved, statement of uniformity; it is not a force. In no sense is it a power that can control the facts.

And yet, whilst submitting its laws to the sifting and refining control of relevant fact, Science still remains self-governed. Its submission to Fact presupposes a fidelity to its own fundamental principles, for it is these alone which determine how Science shall study Fact. On the other hand, the fundamental assumption of Science, the Inductive Postulate, is not arbitrary. It has its root in the protest of the scientific spirit against the anthropomorphisms and animisms of pre-scientific ages (vide Chapter XLVII.), and testifies to the deep conviction of modern Science that Nature is the expression of Natural Law. It is out of this belief in the immanent laws of Nature that the ideal laws of Science have tentatively and gradually taken shape, bringing Nature at last, through man, into self-conscious possession of its own intrinsic orderliness.

Is all Inductive Explanation Causal ?

We may divide our answer to this question under two main heads:

1. All complete Scientific Explanation is directly or indirectly 'causal' in the sense which this word properly bears in Science.

It may be argued that, so long as we are simply inquiring how an object or fact is constituted, asking what are the simple elements or factors out of which it is constructed, the explanation is substantial, not causal. But this mere analysis of a fact into its factors is no explanation. The fact is explained only when we can show how it is the product of these factors. Indeed, Science, in last resort, reduces all questions concerning the coexistence of properties in a thing or substance to questions of causal connexion. So long as we are studying the connexions of what we take to be systematic in nature, we are studying causal connexions, whether these connexions be coexistences or sequences.

Uniformities of coexistence are the most obvious uniformities in Nature. Every natural classification, so far as it is natural, is a record of Nature's correlated facts-i.e., of uniformities of coexistence. The name of a class is the sign by which we recognize the coexistence of a multitude of properties. For instance, by 'Gold' we understand a metal of high specific gravity, high meltingpoint, low chemical affinities, great ductility, yellow colour, etc. In the case of the higher divisions of a natural classification we are furnished with a similar clue to coexistent properties. For instance, 'Monocotyledon' is a sign whereby we are apprised of the whole list of the coexistences expressed in its definition. Again, the inferences that can be drawn from a natural classification are all. expressive of the coexistence of correlated properties.

Correlations or coexistences-e.g., that of two such properties as the ruminating habit and divided feet-in most cases can only be empirically formulated.