Given for one instant an intelligence which could comprehend all the forces by which nature is animated and the respective situation of the beings who compose it—an intelligence sufficiently vast to submit these data to analysis—it would embrace in the same formula the movements of the greatest bodies of the universe and those of the lightest atom; for it, nothing would be uncertain and the future, as the past, would be present to its eyes. The human mind offers, in the perfection which it has been able to give to astronomy, a feeble idea of this intelligence. Its discoveries in mechanics and geometry, added to that of universal gravity, have enabled it to comprehend in the same analytical expressions the past and future states of the system of the world.

The faculty by which man is differentiated from the lower animals is his reasoning power. But the devout believer renounces reason, refuses to explain the things which surround him, the innumerable natural phenomena, because his religious faith is enough for him. The brain loses the habit of thinking; and this religious sottishness hurls mankind back into animalism.

What animals and man have in common is, first of all, sensorial and instinctual intelligence, then the faculties of the senses, and finally basic feelings. What is proper to man alone is the intellect open to the Absolute; and also, owing to that very fact, reason, which extends the Intellect in the direction of relativity; and consequently it is the capacity for integral knowledge, for sacralization, and for ascension. Man shares with animals the wonder of subjectivity − but strangely a wonder that is not understood by the evolutionists; however, the subjectivity of animals is only partial, whereas that of man is total; the sense of the Absolute coincides with totality of intelligence.

We like to believe that Man is in some subtle way superior to the rest of creation. It is best if he can be shown to be necessarily superior, for then there is no danger of him losing his commanding position.

We may not be the center of the universe and the telos of evolution, but we are concrete embodiments of cosmic processes in their particular terrestrial variation. And, albeit accidentally, we did happen to evolve a most remarkable property: self -reflection. In virtue of this we may be among the very few species of natural systems in the universe which are able not only to sense the world and respond to it, but to know their own sensations and come to reasoned conclusions about the nature of the universe. To be a man is thus to have the almost unique opportunity of getting to know oneself and the world in which one lives. It is surely shortsighted to disregard this opportunity and confine oneself solely to the business of living. A failure to exploit our capability for rational knowledge is, moreover, contrary to the business of living.

Mother, recently I have discovered the one way in which human beings differ completely from other animals. Man has, I know, language, knowledge, principles, and social order, but don't all the other animals have them too, granted the difference of degree? Perhaps the animals even have religions. Man boasts of being the lord of all creation, but it would seem as if essentially he does not differ in the least from other animals. But, Mother, there was one way I thought of. Perhaps you won't understand. It's a faculty absolutely unique to man - having secrets. Can you see what I mean?

Man is not just another animal. Our species possesses something unique, a privilege that distinguishes us from all other life forms: Reason.

Man only is endowed with wisdom so as to understand religion, and this is the principal if not the only difference betwixt him and dumb animals; for other things that seem peculiar to him, though they are not the same in them, yet they appear to be alike … What is there more peculiar to man than reason, and foresight? Yet there are animals which make several different ways of retiring from their dens; that when in danger they may escape; which without understanding and forethought they could not do. Others make provision for the future.

If the human mind can understand the universe, it means the human mind is fundamentally of the same order as the divine mind. If the human mind is of the same order as the divine mind, then everything that appeared rational to God as he constructed the universe, it's "geometry," can also be made to appear rational to the human understanding, and so if we search and think hard enough, we can find a rational explanation and underpinning for everything. This is the fundamental proposition of science.

It has been said that man is a rational animal; while this formulation is insufficient and ill-sounding, it nonetheless points to an undeniable truth, though in an elliptical fashion, for the rational faculty actually serves to underscore the transcendence of man in relation to the animal. Man is rational because he possesses the Intellect, which by definition has a capacity for the absolute and therefore a sense of the relative; and he possesses the Intellect because he is made "in the image of God", which, moreover, he demonstrates physically by his corporeal form and his cranial form, as well as by his vertical posture, then by language and his productive capacity. Man is a theophany in his form as much as in his faculties.

We are the one creature to whom natural selection has bequeathed a brain complex enough to comprehend the laws that govern the universe. And we should be proud that we are the only species that has figured out how we came to be.

It is in the world of ideas and in the relation of his brain to the universe itself that the superiority of Man lies. The rise of Man may justly be described as an adventure in ideas.

But then arises the doubt, can the mind of man, which has, as I fully believe been developed from a mind as low as that possessed by the lowest animal, be trusted when it draws such grand conclusions?

Man had in the beginning no power of analysis or synthesis approaching that of the spider, or even of the honey-bee; he had acute sensibility to the higher forces. Fire taught him secrets that no other animal could learn; running water probably taught him even more, especially in his first lessons of mechanics; the animals helped to educate him, trusting themselves into his hands merely for the sake of their food, and carrying his burdens or supplying his clothing; the grasses and grains were academies of study.