III. (A A I. FIG. III.)

All cases of ignorance are cases in which a crime is excused, Such cases are instances of an absence of will or intent; Therefore some cases of absence of will are cases in which crimes are excused.

IV. (A A A. FIG. I.)

The supposition that matter cannot move of itself implies the existence of a higher moving power,

What we adopt is the supposition, &c.;

Therefore we adopt the view that a higher moving power exists.

v. (EAE. FIG. 1.)

The fact that the moon presents always the same face to the earth implies that she has no diurnal revolution on her axis,

But she does present the same face to the earth;
Therefore she cannot go through the diurnal revolution.

VI. (U E E. FIG. 1.)

All the times when the moon comes between the earth and the

sun, are the sole cases of a solar eclipse,

The 11th of February is not such a time;

Therefore the 11th of February will exhibit no eclipse of the

sun.

VII. (U A A. FIG. 1.)

All the times when the earth's shadow falls on the moon, are the sole cases of a lunar eclipse,

The 5th of June is such a time;

Therefore the 5th of June will be the occasion of an eclipse.

VIII. (A E E. FIG. II.)

The case of the earth being of equal density throughout would imply its being 24 times as dense as water,

But in fact, it is not 24 times as dense as water, but 5 times; Therefore it is not of equal density.

IX. (E AE. FIG. II.)

No cases of excessive dew are cases of cloudy night,
But this night is cloudy;

Therefore the dew will not be excessive.

Other modes might be added, but these may suffice to exhibit the nature of the conditional syllogism, together with its affinity to the regular forms. That peculiar connexion between two facts which constitutes the one cause and the other effect, offers a problem worthy of the study of the metaphysician.*

* The principal opinions upon the source of our idea of cause and effect may be thus sketched :

i. Locke refers this idea to sensation. We see that one thing has the power to create, or generate, or make, or alter another thing, and such powers we call causing, and the things that have them are causes. Hum. Und. 11. 26. § 2.

ii. Hume rejects the notion that the fact which we call a cause exercises any power whatever over the effect. But from constantly observing the association or sequence of two facts, we begin to see their invariable connexion, and to represent one as the cause of the other. (Essays, vol. ii. p. 86.) A number of observations is thus a necessary condition of our forming this idea. But why do we give it a name that distinguishes it from sequence, if it is mere sequence? The sunset always

But that the two are connected, and that their relation resembles in many particulars that of subject

follows a flood tide, at a greater or less interval; but no one associates them under the idea of causation.

iii. Leibniz assigns to everything that exists a certain force or power, and thus constitutes it a cause. Existence, indeed, is measured by power. Whilst Locke, as Hume remarks, infers causation from the fact that things come into being and are changed, Leibniz regards power and causation as primary attributes of all being, not inferred from but implied by it. Nouveaux Essais, B. 11.

iv. Kant considered the notion of cause and effect as one of the forms of the understanding, one of the conditions under which we must think. We are compelled by a law of our mind to arrange the impressions of our experience according to this form, making one thing a cause and another an effect ; but whether there exists in the objects themselves that which we mean by a cause and an effect, we cannot determine. (Critique. Transcendental Analytic.)

v. The view of Maine de Biran is chiefly known through the writings of Victor Cousin and others. According to him (and I quote through his critics only), the notion of cause originates with our consciousness of the power of will, which recognizes the will as the cause of our actions; and we transfer this personal power by a kind of analogy to all the operations of nature.

vi. Sir William Hamilton traces the idea of causality to that limitation of our faculties which prevents us from realizing an absolute commencement or an absolute termination of being. When we think of a thing, we know that it has come into being as a phenomenon, but we are forced to believe that the elements and facts that produced the phenomenon existed already in another form. In the world to which our observations are confined, being does not begin; it only changes its manifesta. tions; the stock of forces (so to speak) is not augmented,

and predicate in an ordinary proposition, is all that a logician need ascertain. An ordinary proposition asserts that the thought of one thing or attribute draws with it, or implies, the thought of another thing or attribute; the conditional judgment declares that the thought of one fact brings with it the thought of another fact; but whether the connection of the facts is such as to invest them with a particular property, or arises only in the mind, and is one of the forms of thought under which the mind views external impressions, we shall not inquire. If the inferences in the categorical syllogism might be described by the principle Nota notæ est nota rei ipsius (see 93.), the corresponding form of conditional syllogism would be explained by Effectus effectûs est effectus causæ. And so throughout might the parallel be traced between every categorical mode and a parallel hypothetical.

One distinction of causes must not be forgotten, that which is between the cause of our knowing a fact (causa cognoscendi), and the cause of the fact's existence (causa essendi). When we say "the ground

though their direction and operations alter. By our idea of causation we express this belief; the causes of anything arc the forces and elements of it, before they took shape in it. But see an admirable Conspectus of the theories of Causality with a much fuller account of his own view in Sir W. H.'s Discussions, &c. p. 585, fol.

is wet, because it has rained," we assign to the rain the latter character; it is the cause of the ground actually being in this state. But the cause may change places with the effect; "it has rained because the ground is wet "where the wetness of the ground is the cause of our being sure there has been rain, and this is all that we mean to assert, and not the absurd proposition that the wetness which followed, could bring about the rain which preceded. The inquiry into causes which occupies the inductive philosopher applies to causes of things being, and not properly to causes of our knowing things.

§ 107. Disjunctive Syllogisms.

An argument in which there is a disjunctive judgment (§ 71.) is called a disjunctive syllogism. A pure disjunctive argument (i. e. one in which no immediate inference has to be supplied) may be at once referred to its proper mode, by ascertaining the quantity and quality of the disjunctive judgment in it. The principal forms of such syllogisms are annexed.

1. (In A U A. Fig. 1.)

CD and E are P,

All S is either C D or E;

... All S is P.