To these spurious principles must be added some others of great affinity with them… First, that by which we assume that everything in the universe is done according to the order of nature, which principle by Epicurus was proclaimed without any restriction, and by all other philosophers unanimously with extremely rare exceptions, not to be admitted but from supreme necessity.

Several actual worlds without one another are not, therefore, impossible by the very concept, as Wolf hastily concluded from the notion of a complex or multiplicity which he deemed sufficient to a whole, as such, but only on condition that there exist but one necessary cause of all things. If several are admitted, several worlds without one another will be possible in the strictest metaphysical sense.

A whole from necessary substances is impossible. The whole, therefore, of substances is a whole of contingent things, and the world consists essentially of only contingent things.

It is absurd to excite reason against the primary postulates of pure time, as, for example, continuity, etc., since they follow from laws prior and superior to which nothing is found, and since reason herself in the use of the principle of contradiction cannot dispense with the support of this concept, so primitive and original is it.

Of Space

The concept of space is not abstracted from external sensations.

The concept of space, therefore, is a pure intuition, being a singular concept, not made up by sensations, but itself the fundamental form of all external sensation.

Nature, therefore, is subject with absolute precision to all the precepts of geometry as to all the properties of space there demonstrated, this being the subjective condition, not hypothetically but intuitively given, of every phenomenon in which nature can ever be revealed to the senses.

Space is employed as the type even of the concept of time itself, representing it by a line, and its limits — moments — by points. Time, on the other had, approaches more to a universal and rational concept, comprising under its relations all things whatsoever, to wit, space itself, and besides, those accidents which are not comprehended in the relations of space, such as the thoughts of the soul. Again, time, besides this, though it certainly does not dictate the laws of reason, yet constitutes the principal conditions tinder favor of which the mind compares its notions according to the laws of reason. Thus, I cannot judge what is impossible except by predicating a and not-a of the same subject at the same time.

The question of the principle of the form of the intelligible world turns, therefore, upon making apparent in what manner it is possible for several substances to be in mutual commerce, and for this reason to pertain to the same whole, which is called world. We do not here consider the world, let it be understood, as to matter, that is, as to the nature of the substances of which it consists, whether they be material or immaterial, but as to form, that is to say, how among several things taken separately a connection, and among them all, totality can have place.

The sham cause in physical influence consists in rashly assuming that the commerce of substance and transitive forces is sufficiently knowable from their mere existence. Hence it is not so much a system as rather the neglect of all philosophical system as a superfluity in the argument. Freeing the concept from this defect, we shall have a species of commerce alone deserving to be called real, and from which the whole constituting the world merits being called real, and not ideal or imaginary.

The second is the partiality for unity proper to the philosophical mind, whence this wide-spread canon has flown forth: principles are not to be multiplied beyond supreme necessity, to which we give in our adhesion, not because we have insight into causal unity in the world either by reason or experience, but as seeking it by an impulse of the intellect which seems to itself to have by thus much advanced in the explication of phenomena, by as much as it is granted to it to descend from the same principle to a greater number of consequences,

The third of this kind of principles is : matter neither originates nor perishes; all the changes in the world concern form only ; a postulate which on the recommendation of common sense has spread through all philosophical schools, not because it is to be taken as having been found so, or as having been demonstrated by arguments a priori, but because if we were to admit that matter itself is fleeting and transitory, nothing at all that is stable and lasting would be left any longer to serve for the explication of phenomena according to universal and perpetual laws, and hence nothing at all would be left for the exercise of the intellect.

I freely admit that the remembrance of David Hume was the very thing that many years ago first interrupted my dogmatic slumber and gave a completely different direction to my researches in the field of speculative philosophy.

Reason in a creature is a faculty of widening the rules and purposes of the use of all its powers far beyond natural instinct; it acknowledges no limits to its projects. Reason itself does not work instinctively, but requires trial, practice, and instruction in order gradually to progress from one level of insight to another. Therefore a single man would have to live excessively long in order to learn to make full use of all his natural capacities. Since Nature has set only a short period for his life, she needs a perhaps unreckonable series of generations, each of which passes its own enlightenment to its successor in order finally to bring the seeds of enlightenment to that degree of development in our race which is completely suitable to Nature’s purpose. This point of time must be, at least as an ideal, the goal of man’s efforts, for otherwise his natural capacities would have to be counted as for the most part vain and aimless. This would destroy all practical principles, and Nature, whose wisdom must serve as the fundamental principle in judging all her other offspring, would thereby make man alone a contemptible plaything.

Nature has willed that man should, by himself, produce everything that goes beyond the mechanical ordering of his animal existence, and that he should partake of no other happiness or perfection than that which he himself, independently of instinct, has created by his own reason.

Nature does nothing in vain, and in the use of means to her goals she is not prodigal. Her giving to man reason and the freedom of the will which depends upon it is clear indication of her purpose. Man accordingly was not to be guided by instinct, not nurtured and instructed with ready-made knowledge; rather, he should bring forth everything out of his own resources.

The means employed by Nature to bring about the development of all the capacities of men is their antagonism in society, so far as this is, in the end, the cause of a lawful order among men.

The greatest problem for the human race, to the solution of which Nature drives man, is the achievement of a universal civic society which administers law among men.

This problem is the most difficult and the last to be solved by mankind.

The master is himself an animal, and needs a master. Let him begin it as he will, it is not to be seen how he can procure a magistracy which can maintain public justice and which is itself just, whether it be a single person or a group of several elected persons. For each of them will always abuse his freedom if he has none above him to exercise force in accord with the laws. The highest master should be just in himself, and yet a man. This task is therefore the hardest of all; indeed, its complete solution is impossible, for from such crooked wood as man is made of, nothing perfectly straight can be built. That it is the last problem to be solved follows also from this: it requires that there be a correct conception of a possible constitution, great experience gained in many paths of life, and — far beyond these — a good will ready to accept such a constitution. Three such things are very hard, and if they are ever to be found together, it will be very late and after many vain attempts.

The problem of establishing a perfect civic constitution is dependent upon the problem of a lawful external relation among states and cannot be solved without a solution of the latter problem.

In man (as the only rational creature on earth) those natural capacities which are directed to the use of his reason are to be fully developed only in the race, not in the individual.

All natural capacities of a creature are destined to evolve completely to their natural end.

Through laziness and cowardice a large part of mankind, even after nature has freed them from alien guidance, gladly remain immature. It is because of laziness and cowardice that it is so easy for others to usurp the role of guardians. It is so comfortable to be a minor!

The guardians who have kindly undertaken the supervision will see to it that by far the largest part of mankind, including the entire "beautiful sex," should consider the step into maturity, not only as difficult but as very dangerous. After having made their domestic animals dumb and having carefully prevented these quiet creatures from daring to take any step beyond the lead-strings to which they have fastened them, these guardians then show them the danger which threatens them, should they attempt to walk alone.

It is difficult for the isolated individual to work himself out of the immaturity which has become almost natural for him. He has even become fond of it and for the time being is incapable of employing his own intelligence, because he has never been allowed to make the attempt. Statutes and formulas, these mechanical tools of a serviceable use, or rather misuse, of his natural faculties, are the ankle-chains of a continuous immaturity. Whoever threw it off would make an uncertain jump over the smallest trench because he is not accustomed to such free movement. Therefore there are only a few who have pursued a firm path and have succeeded in escaping from immaturity by their own cultivation of the mind.

There will always be some people who think for themselves, even among the self-appointed guardians of the great mass who, after having thrown off the yoke of immaturity themselves, will spread about them the spirit of a reasonable estimate of their own value and of the need for every man to think for himself.

A public can only arrive at enlightenment slowly. Through revolution, the abandonment of personal despotism may be engendered and the end of profit-seeking and domineering oppression may occur, but never a true reform of the state of mind. Instead, new prejudices, just like the old ones, will serve as the guiding reins of the great, unthinking mass. All that is required for this enlightenment is freedom; and particularly the least harmful of all that may be called freedom, namely, the freedom for man to make public use of his reason in all matters. But I hear people clamor on all sides: Don't argue! The officer says: Don't argue, drill! The tax collector: Don't argue, pay! The pastor: Don't argue, believe!

The public use of a man's reason must be free at all times, and this alone can bring enlightenment among men...

Whatever concept one may hold, from a metaphysical point of view, concerning the freedom of the will, certainly its appearances, which are human actions, like every other natural event are determined by universal laws. However obscure their causes, history, which is concerned with narrating these appearances, permits us to hope that if we attend to the play of freedom of the human will in the large, we may be able to discern a regular movement in it, and that what seems complex and chaotic in the single individual may be seen from the standpoint of the human race as a whole to be a steady and progressive though slow evolution of its original endowment.

Since men in their endeavors behave, on the whole, not just instinctively, like the brutes, nor yet like rational citizens of the world according to some agreed-on plan, no history of man conceived according to a plan seems to be possible, as it might be possible to have such a history of bees or beavers. One cannot suppress a certain indignation when one sees men’s actions on the great world-stage and finds, beside the wisdom that appears here and there among individuals, everything in the large woven together from folly, childish vanity, even from childish malice and destructiveness. In the end, one does not know what to think of the human race, so conceited in its gifts.

What is the use of working toward a lawful civic constitution among individuals, i.e., toward the creation of a commonwealth? The same unsociability which drives man to this causes any single commonwealth to stand in unrestricted freedom in relation to others; consequently, each of them must expect from another precisely the evil which oppressed the individuals and forced them to enter into a lawful civic state. The friction among men, the inevitable antagonism, which is a mark of even the largest societies and political bodies, is used by Nature as a means to establish a condition of quiet and security. Through war, through the taxing and never-ending accumulation of armament, through the want which any state, even in peacetime, must suffer internally, Nature forces them to make at first inadequate and tentative attempts; finally, after devastations, revolutions, and even complete exhaustion, she brings them to that which reason could have told them at the beginning and with far less sad experience, to wit, to step from the lawless condition of savages into a league of nations. In a league of nations, even the smallest state could expect security and justice, not from its own power and by its own decrees, but only from this great league of nations … from a united power acting according to decisions reached under the laws of their united will.

I am an investigator by inclination. I feel a great thirst for knowledge and an impatient eagerness to advance, also satisfaction at each progressive step. There was a time when I thought that all this could constitute the honor of humanity, and I despised the mob, which knows nothing about it. Rousseau set me straight. This dazzling excellence vanishes; I learn to honor men, and would consider myself much less useful than common laborers if I did not believe that this consideration could give all the others a value, to establish the rights of humanity.

If the truth shall kill them, let them die.

Have patience awhile; slanders are not long-lived. Truth is the child of time; erelong she shall appear to vindicate thee.

The innocent sounding First Thesis, taken seriously, forces us to move our attention away from the individual toward humanity. Since there are no limits to the application of reason, and reason does not work instinctively, but requires "trial, practice, and instruction in order to gradually progress from one level of insight to another," individual human beings do not live long enough to learn the full use of reason. However, we find nature setting a short period for individual lives, but producing a series of generations in which each passes its own accomplishments onto its successor. The only way to make the capability of reasoning consistent with the First Thesis is to assume that rationality is to be fully developed only in the race, not in the individual.

The very fact that the totality of our sense experiences is such that by means of thinking (operations with concepts, and the creation and use of definite functional relations between them, and the coordination of sense experiences to these concepts) it can be put in order, this fact is one which leaves us in awe, but which we shall never understand. One may say " the eternal mystery of the world is its comprehensibility." It is one of the great realizations of Immanuel Kant that the setting up of a real external world would be senseless without this comprehensibility.

All that is necessary is the statement of a set of rules, since without such rules the acquisition of knowledge in the desired sense would be impossible. One may compare these rules with the rules of a game in which, while the rules themselves are arbitrary, it is their rigidity alone which makes the game possible. However, the fixation will never be final. It will have validity only for a special field of application (i.e. there are no final categories in the sense of Kant).

In an order so extended as to transcend the comprehension and possible guidance of any single mind, a unified will can indeed hardly determine the welfare of its several members in terms of some particular conception of justice, or according to an agreed scale. Nor is this due merely to the problems of anthropomorphism. The insight that general rules must prevail for spontaneity to flourish, as reaped by Hume and Kant, has never been refuted, merely neglected or forgotten.

Then there's philosophy -- supposed to tackle everything. Does it? All any philosopher ever comes out with is exactly what be walked in with -- except for those self-deluded who prove their assumptions by their conclusions, in a circle. Like Kant.

Each sensory system first analyzes and deconstructs, then restructures the raw, incoming information to its own built-in connections and rules—shades of Immanuel Kant.

To be is to do.

Do what is right, though the world may perish.

In the metaphysical elements of aesthetics the various nonmoral feelings are to be made use of; in the elements of moral metaphysics the various moral feelings of men, according to the differences in sex, age, education, and government, of races and climates, are to be employed.

In the natural state no concept of God can arise, and the false one which one makes for himself is harmful. Hence the theory of natural religion can be true only where there is no science; therefore it cannot bind all men together.

Man has his own inclinations and a natural will which, in his actions, by means of his free choice, he follows and directs. There can be nothing more dreadful than that the actions of one man should be subject to the will of another; hence no abhorrence can be more natural than that which a man has for slavery. And it is for this reason that a child cries and becomes embittered when he must do what others wish, when no one has taken the trouble to make it agreeable to him. He wants to be a man soon, so that he can do as he himself likes.

Suicide evokes revulsion with horror, because everything in nature seeks to preserve itself: a damaged tree, a living body, an animal; and in man, then, is freedom, which is the highest degree of life, and constitutes the worth of it, to become now a principium for self-destruction? This is the most horrifying thing imaginable. For anyone who has already got so far as to be master, at any time, over his own life, is also master over the life of anyone else; for him, the door stands open to every crime, and before he can be seized he is ready to spirit himself away out of the world. So suicide evokes horror, in that a man thereby puts himself below the beasts. We regard a suicide as a carcase, whereas we feel pity for one who meets his end through fate.

A person who already displays … cruelty to animals is also no less hardened towards men. We can already know the human heart, even in regard to animals.

The more we devote ourselves to observing animals and their behaviour, the more we love them, on seeing how gready they care for their young; in such a context, we cannot even contemplate cruelty to a wolf. Leibnitz put the grub he had been observing back on the tree with its leaf, lest he should be guilty of doing any harm to it. It upsets a man to destroy such a creature for no reason, and this tenderness is subsequently transferred to man.