In the course of his discussion of Rene Descartes, Belloc mentions that Descartes did not deal with the proof of things outside of ourselves. In doing so, Belloc cites the names of Aristotle and St. Thomas Aquinas:
There is no rational process by which the reality of the external universe can be discovered; all we know is that it can be confidently affirmed. Aristotle, who might be called reason itself; St. Thomas, whose whole process was that of beginning with a doubt, and examining all that there was to be said for that doubt before the denial of it and the corresponding certitude could be arrived at, both postulate this second truth. Not only am I, I, but that which is not myself is just as real as I am, and what is more, can be and is apprehended by myself.
That is, like all true philosophy, common sense. Your plain man, who is made in the image of God and who, so long as his reason and conscience are not warped, is on the right lines, has no patience with any denial of it. The whole of human society takes it for granted and must take it for granted. The witness in a Court of Justice, the man conducting his own affairs, the simplest activities of daily life, takes for granted as absolutely certain, not only the external universe in which we live, but our own power of apprehending it.
In his 1937 book, The Crisis of [Our] Civilization, based upon his lectures at Fordham University, Belloc explains St. Thomas Aquinas' place in Church History and philosophy:
The XIIIth century was that moment in which the high Middle Ages reached their summit. It was that moment in which the Catholic culture came, in the civic sense of the word “ culture,” to maturity. It was probably the supreme moment of our blood, at any rate one of the very greatest moments. Never had we had such a well-founded society before, never have we since had any society so well founded or so much concerned with justice. A proof, if proof were needed, of the greatness of that time is the scale of the chief public characters, already named: St. Louis the King, Ferdinand of Castile, St. Dominic and St. Francis, with their new orders of friars, Edward I of England, and, in philosophy, which determines all, the towering name of St. Thomas Aquinas. He established during that great time a body of coordinated doctrine and philosophy which no one had yet possessed. The scale of his work is on a par with its cultural value. He seemed to have put his seal upon the civilization which he adorned, and, through his establishment of right reason in philosophy, his marriage of Catholicism with the Aristotelian wisdom, to have set up a structure that would endure for ever and give a norm to our civilization.
In his great study of St. Thomas Aquinas, Belloc's friend G.K. Chesterton describes this "marriage of Catholicism with the Aristotelian wisdom":
In a word, St. Thomas was making Christendom more Christian in making it more Aristotelian. This is not a paradox but a plain truism, which can only be missed by those who may know what is meant by an Aristotelian, but have simply forgotten what is meant by a Christian. As compared with a Jew, a Moslem, a Buddhist, a Deist, or most obvious alternatives, a Christian means a man who believes that deity or sanctity has attached to matter or entered the world of the senses. Some modern writers, missing this simple point, have even talked as if the acceptance of Aristotle was a sort of concession to the Arabs; like a Modernist vicar making a concession to the Agnostics. They might as well say that the Crusades were a concession to the Arabs as say that Aquinas rescuing Aristotle from Averrhoes was a concession to the Arabs. The Crusaders wanted to recover the place where the body of Christ had been, because they believed, rightly or wrongly, that it was a Christian place. St. Thomas wanted to recover what was in essence the body of Christ itself; the sanctified body of the Son of Man which had become a miraculous medium between heaven and earth. And he wanted the body, and all its senses, because he believed, rightly or wrongly, that it was a Christian thing. It might be a humbler or homelier thing than the Platonic mind; that is why it was Christian. St. Thomas was, if you will, taking the lower road when he walked in the steps of Aristotle. So was God, when He worked in the workshop of Joseph.
. . . these two great men stand for the reaction upon Catholicism as a whole produced by the upheaval of the sixteenth century and early seventeenth century — all that confused movement which has been called the twin warring brothers, Reformation and Renaissance. And when we consider all the effect of them, the way in which Descartes has led to sceptical rationalism, Pascal to a contempt for doctrine and a sort of cloud over the mind in which men lost the Faith, the most remarkable thing still is that both men remained firmly of the Faith, lived in it and died in it. They both were living proofs that the Gates of Hell had not prevailed and that the Church had proved its power to survive.
To return to Belloc's views of Descartes and Pascal, Belloc sums them up thus:
For my own part the two things that stand out most vividly in the case of either man are these: Of Descartes, that he had the humility, the faith and the devotion to make the pilgrimage to Loretto; of Pascal, the splendour of his death.
The Holy House of Loreto is in Italy and Descartes went there in 1623. Pascal suffered from great pains in his stomach for years. When he died on August 19, 1662 in Paris his last words were: "May God never abandon me."