Book 4
(synthetical)

Laws governing the activity of the soul -
laws according to which the rational principle operates

Introduction

1278. Logic and Christian feeling are the two characteristics of the people of Italy. Writers true to logic and religion were, therefore, acceptable to the nation. This was not the case with others who, abandoning right reasoning and faith, were either censured or forgotten by the public despite their intelligence and erudition. These characteristics explain the progress made in the natural sciences by Italy as she sat at the feet of Galileo; they also explain her tardiness in heeding the call of philosophy in the 16th century.
Logic was an inevitable part of the mathematical sciences. The immortal Galileo ensured its presence in the physical sciences where the study of nature, entrusted to rigorous reasoning, could never clash with religion.

Unfortunately, the nature of metaphysical investigations is not on a par with the nature of mathematics. Illogical metaphysicians are not immediately condemned as mistaken. Nor did heaven grant to philosophy a scholar like Galileo. 16th century philosophers, tainted with the human passions and vices from which philosophy as a whole is not immune, were unable to shake off the unwholesome influence of northern heresy. But such sophists were rejected by the Italian spirit which sometimes went to the excess of burning the impious. For her part, Italy, a desert philosophically speaking, was incapable of attaining nationhood.

Peoples of different blood and talent, brought up in more restricted traditions and less venturesome, were able to unite and cultivate a national spirit almost instinctively, without the developed culture proper to systematic knowledge. This was not the case in Italy, which could achieve nationhood only under the guide of truthful philosophy. The Italian people must first be brought together by intellectual principles which, because they are logical, are also religious. This is the first bond uniting the peoples of the peninsula, and it is hopeless to presume that other ties can achieve the same end without this primary uniting factor.

If religion and logic are the only feelings which remain common to the Italian family, it is inevitable that philosophy must demonstrate its capacity for uniting the peoples of Italy in the school of truth. From the depths of the nation it must draw religion and logic, two extremely powerful seeds of good civic order, and make us realise that our minds aim at the same rectitude, our spirits at the same belief and our ambition at the glory of the Christian pontificate. Harmony amongst Italians will thus spring from their own intimate character and nature; truth, and the Almighty himself, will act as their mediators. This harmony will be firm and lasting, capable of development and of fulfilling every civic need; it has its source where man resides as lord, that is, in reason; here alone he is a noble servant worshipping his Creator. Geometry and physics, studied with such passion by Italians, is only a delightful apprenticeship for this.

1279. Divine Providence has, I think, kept Italians exclusively occupied in mathematical and physical sciences to train them for the higher, more important philosophical and civil sciences (sciences for which we were also prepared by our literature and arts, the envy of other nations). Plato was wise when he excluded from his divine lessons students who had not already been trained in geometry; Socrates' courtesy and grace, seen at their best when employed in the service of philosophy, were very suitable for adorning the philosophical schools.

The logic of natural sciences is not proper to them; it does not differ from the logic required by metaphysical disciplines. Logic is one, just as the art of thought is one, and truth is one. Taking the logic of natural sciences as peculiar to them has led many of our best scientists to despise metaphysics which, they think, rejects the exact reasoning that always goes hand in hand with sciences of mere quantity. And such scientists would be right if my attackers — those who blame me for wanting Italian philosophy to faithfully obey the common laws of human thought, to begin from observation and the verification of facts, to reason exactly on the basis of facts — were themselves correct. But attacks of this kind will not lead me to repudiate the quasi-experimental method which I have recommended to those of our nation who have already begun to philosophise, and whom, as far as I know, I have supported in their philosophical investigations. There is no other method. Certainly, I have no regret in leaving to the devotees of the ancient oracles the divine intuition which, it would seem, led them to contemplate and receive from the voice of their god everything created and uncreated. Let them, and those drunk with poetic inspiration, be banned from entering the temple of philosophy. Without such a prohibition, Italians will never be philosophers, but rest content with their natural state as poets.

1280. This is why I have headed the new book: Laws according to which the rational principle operates. Here, too, I want to imitate natural scientists who collect similar facts about which they take accurate, careful notes to see what is identical in them and to discover the constant modes of operation of their frequently hidden causes. Such constant modes are called 'laws'. What our scientists call laws of nature are simply the identity and constancy of effects as they appear in the reciprocal action and passions of the corporeal substances making up the world. Scientists then reasonably induce the way in which things act from the sameness discovered in effects. From there, they go on to argue that the cause is so formed or natured or disposed that it can only be used in that way. They rightly call such necessary action, always carried out in the same way, 'law'. Law 'indicates necessity that determines action' although the necessity may sometimes be physical, sometimes moral; it first points to moral necessity before being transported to the field of physical necessity.

I have to follow the same path in studying operations and effects dependent on invisible and spiritual causes. Thought as dialectic requires the same process: first, extremely accurate observation to bring together the operations of the rational principle; then, careful examination of what is identical in these operations; next, induction about the constant way in which the cause operates; and finally a conclusion showing that this constancy and uniformity of operation must have a correlative necessity obliging the cause to conform its operations in this way. This necessity, which we call 'law', must have its root in the very nature of the operating substance or cause. Nature and substance are immutable, immanent acts relative to their passing actions and effects.

1281. Because the laws we bring together will be very numerous, I shall try to put some order into the work by first considering the principal sources, the principal elements, which give rise to the operations of the rational principle, operations which we have to observe. These elements, when accurately distinguished, will immediately give us a first, general classification of the laws we intend to investigate.