Cicero

..as a philosopher, I have a right to ask for a rational explanation of religious faith. (Cicero)

..it is improbable that the material substance which is the origin of all things was created by divine Providence. It has and has always had a force and nature of its own. (Cicero)

Those dwelling near the cataracts grow used to the noise and therefore cannot hear it: so too mankind cannot hear the music of the spheres. (Cicero, Dream of Scorpio)

As a man who knows how to make his education into a rule of life not a means of showing off; who can control himself and obey his own principles. (Cicero)

There are many questions in philosophy to which no satisfactory answer has yet to be given. But the question of the nature of the gods is the darkest and most difficult of all. Yet an answer to this question could shed the clearest light upon the nature of our own minds and also give us the essential guidance which we need in our religion. So various and so contradictory are the opinions of the most learned men on this matter as to persuade one of the truth of the saying that philosophy is the child of ignorance: and that the philosophers of the Academy have been wise in withholding their consent from any proposition that has not been proved. There is nothing worse than a hasty judgement, and nothing could be more unworthy of the dignity and integrity of a philosopher than uncritically to adopt a false opinion or to maintain as certain some theory which has not been fully explored and understood. (Cicero)

I ask you both, why did these creators of the world suddenly wake up, after apparently having been asleep from time immemorial? Even if there was then no world, time must still have been passing. Time, I say, and not those periods of time which are measured by the number of nights and days in the course of a year. I admit that these depend upon the circular movement of the world. But from all eternity there has been an infinite time, unmeasurable by any periodical divisions. This we can understand from the analogy of space. But we cannot even conceive that once upon a time there was no time at all. (Cicero)

Are you not ashamed as a scientist, as an observer and investigator of nature, to seek your criterion of truth from minds steeped in conventional beliefs? (Cicero)

Freedom suppressed and again regained bites with keener fangs than freedom never endangered. (Cicero)

Marcus Tullius Cicero Biography
Marcus Tullius Cicero (106-43 B.C.), Roman orator and statesman, was born at Arpinum of a wealthy family. He was taken to Rome for his education with the idea of a public career and by 70 B.C. he had established himself as the leading barrister in Rome. In the meantime his political career was well under way and he was elected praetor for the year 66. His ambitious nature enabled him to obtain these honours which could normally only have been conferred upon members of the Roman aristocracy, and was duly elected consul for 63. One of the most permanent features of his political life was his attachment to Pompey. As a politician his greatest failing was his consistent refusal to compromise, as a statesman his ideals were more honourable and unselfish than those of his contemporaries. Cicero was the greatest of the Roman orators, possessing a wide range of techniques and an exceptional command of the Latin tongue. He followed the common practice of publishing his speeches. The information that they give us about contemporary social and political life is greatly increased by his letters, of which there are 900 published posthumously. His deeper thoughts are revealed by a considerable number of writings on moral and political philosophy, on religion and on the theory and practice of rhetoric. (Introduction, The Nature of the Gods, Penguin Classics, 1972)

Cicero - The Nature of the Gods
Introduction
In contrast to the dogmatic claims of Epicureans and Stoics to absolute truth, the Academy proceeded by skeptical examination of all positions in order to find which was most probable, and this way always Cicero's method, so that just as he opposed all absolutism, real or threatened, in government, whether the threat came from Sulla, Catiline, Caesar or Antonius. (Introduction, On the Nature of the Gods)

his careful attention to poetical as well as oratorical style was simply another expression of his philosophical conviction that everything must be presented in the clearest and most attractive manner in order that the nearest approximations of truth in the end emerge. (Introduction, On the Nature of the Gods)

Thus he himself says that he had been interested in philosophy all his life, and when occupied with legal and political work was often most the philosopher when he seemed least interested in philosophy. (Introduction, On the Nature of the Gods)

He said to Atticus at that time that he would rather sit on the little chair his friend had beneath a bust of Aristotle than occupy the ivory throne of office. (p16)Could he not go down to fame as the saviour and benefactor of his country in quite a different sense- as the man who made available to Roman readers the treasures of Greek philosophy and expanded the Latin language for use as a vehicle for abstract thought? (Introduction, On the Nature of the Gods)

If people objected that Latin was not a suitable language for the conveyance of abstract ideas, then he would make it so: if words were needed, he would coin them. And in point of fact he did this very thing. He invented a number of words (such as moralis, essentia, qualitas) which soon became common coin, and left behind him a new style of Latin which enabled Christian theologians and humanistic philosophers for centuries afterwards to discuss the profoundest problems in a language that was in ordinary use among educated people. (Introduction, On the Nature of the Gods)

..we are not mere translators, but contribute our own judgement in deciding what to select and how to present it. (Introduction, On the Nature of the Gods)

Nor is there any philosophical merit in originality: the question to ask of a philosophy is not whether it is original but whether it is true. (Introduction, On the Nature of the Gods)

In the Summer of 45 B.C. Cicero had written the first four installments of his course of Greek philosophy. He had begun with the chief current problem in the theory of knowledge, namely whether we can have certain knowledge, and whether we can trust our eyes and ears.. (Introduction, On the Nature of the Gods)

If the Epicureans are right, the gods are not concerned with the world and make no difference to it; such gods cannot honestly be worshipped, and indeed the Epicureans regarded religion as an evil thing from which mankind should be set free. It seems necessary, therefore, to believe in real gods who make a difference to life on earth, for example, by punishing wickedness and providing for the needs of mankind. Shall we then embrace the Stoic system, which teaches that there is detailed divine control of human affairs? But that system encourages many kinds of superstition and has been subjected to highly damaging criticism. by the Academic school of thought. (Introduction, On the Nature of the Gods)

Book 1
There are many questions in philosophy to which no satisfactory answer has yet to be given. But the question of the nature of the gods is the darkest and most difficult of all. Yet an answer to this question could shed the clearest light upon the nature of our own minds and also give us the essential guidance which we need in our religion. So various and so contradictory are the opinions of the most learned men on this matter as to persuade one of the truth of the saying that philosophy is the child of ignorance: and that the philosophers of the Academy have been wise in withholding their consent from any proposition that has not been proved. There is nothing worse than a hasty judgement, and nothing could be more unworthy of the dignity and integrity of a philosopher than uncritically to adopt a false opinion or to maintain as certain some theory which has not been fully explored and understood. (Cicero)

I ask you both, why did these creators of the world suddenly wake up, after apparently having been asleep from time immemorial? Even if there was then no world, time must still have been passing. Time, I say, and not those periods of time which are measured by the number of nights and days in the course of a year. I admit that these depend upon the circular movement of the world. But from all eternity there has been an infinite time, unmeasurable by any periodical divisions. This we can understand from the analogy of space. But we cannot even conceive that once upon a time there was no time at all. (Cicero)

Are you not ashamed as a scientist, as an observer and investigator of nature, to seek your criterion of truth from minds steeped in conventional beliefs? (Cicero)

The fact is that everything which grows and flourishes contains in itself a natural heat without which it could not grow or flourish. Everything which has within it heat and fire is stirred and enlivened by their motion. And while anything grows and flourishes, this motion is steady and regular. And so long as it remains so with us, our life and consciousness continue. But when this vital warmth grows cold and finally extinct, we ourselves decline and die.
..the veins and arteries throb constantly with a fiery pulse. It has often been observed that if the heart is torn out of any animal, it continues to beat violently like a flickering fire. Therefore everything which lives, whether it is animal or vegetable, lives only by reason of the heat enclosed within it. From which it can be seen that this heat has by nature a vital force within itself which permeates the whole world. (Cicero)

From which it follows that as all the elements of the universe are sustained by heat, so the whole universe is itself preserved through all the ages by a similar power: the more so, because it must be understood that this hot and fiery principle is so infused throughout the whole of nature that it provides the life-force and is the source of all that comes to be, and from it is born and nourished every living creature and every plant whose roots are in the earth.
That which we call Nature is therefore the power which permeates and preserves the whole universe, and this power is not devoid of sense and reason. Every being which is not homogeneous and simple but complex and composite must have in it some organising principle. In man this organising principle is reason and in animals it is a power akin to reason, and from this arises all purpose and desire. (Cicero)

So we see that the parts of the world (for there is nothing in the world which is not a part of the universe as a whole) have sense and reason. So these must be present to a higher and greater degree in that part which provides the organising principle of the whole world. So the universe must be a rational being and the Nature which permeates and embraces all things must be endowed with reason in its highest form. And so God and the world of Nature must be one, and all the life of the world must be contained within the being of God. (Cicero)

..as a philosopher, I have a right to ask for a rational explanation of religious faith. (Cicero)

Cicero in his discussion of the nature of the gods asserts that ‘in the first place it is improbable that the material substance which is the origin of all things was created by divine Providence. It has and has always had a force and nature of its own.’ (Cicero) (Lactantius, Divine Institutions, ii. 8.10)