Thomas Aquinas (1227— 1274) was an important political thinker in medieval western Europe. Born into a noble family, he was an important theorist of Catholicism before his death and was honored as a "saint" after his death. Philosophers consider him a master of scholasticism. Catholicism had an overwhelming advantage in medieval feudal society in western Europe. All aspects of his theory are covered with the cloak of religious theology, and the essence of the theory based on theology is always to maintain the feudal exploitation relationship and the secular and secular feudal rule of monks. In his theological and political thoughts, nothing can represent all this better than God, who has become the source of almost all his thoughts.

Aquinas once said: "God arranges everything in the most admirable way. Everything is arranged to help the generation of goodness, and goodness comes from the same perfect source in everything. It seems that God wants to strengthen the power of good from a single source and weaken the power of evil from various reasons. Therefore, a well-known regime is best controlled by one person alone. " Therefore, in Aquinas' government theory, theological characteristics are very obvious. In his view, the legitimacy of the monarchy undoubtedly comes from God, who arranged such a government. Naturally, people should also fully abide by and fully support it. The purpose of this is obvious, of course, to maintain this long-standing feudal exploitation relationship and give the monarch a strong spiritual and theoretical support for his lifelong rule.

Aquinas believes that people not only have natural and emotional desires, but also have rationality and desire and tendency to pursue a better moral life. The natural law of human moral activities is to seek advantages and avoid disadvantages, and the highest goal pursued by reason is universal and supreme goodness. Man's rationality comes from God, and man's moral activities are only natural commands and laws branded by God on human mind. It can be seen that in Aquinas' view, people's goodness and pursuit all come from God, which deeply embodies the brand of God. It is not enough for people to rely on their own subjective efforts. The key is to rely on God's help. Without God, people can't reach the realm of goodness.

God's creation is hierarchical, divided into "advanced" and "low-level". Aquinas once said: "Since people have wisdom, feeling and physical strength at the same time, these endowments will be arranged by God's will, and they will be in a subordinate position to each other and follow the pattern of the cosmic order. Similarly, a system can also be found between people; Because people with outstanding intelligence naturally enjoy the right to dominate, and people with poor intelligence but strong physical strength seem to be angels who act as slaves. " Therefore, in his view, it is natural that achievements are created by God and conform to God's will.

On the discussion of "law", Aquinas declared that there are four basic laws in the world:

First, the eternal law. It is the norm that God guides and guides the operation of the whole universe, and it is the basis of all laws.

Second, the laws of nature. It is the reflection of God's laws in human reason, which is universal and unchangeable.

Third, the human law, that is, the human law. It is based on the laws clearly stipulated by the laws of nature and is specifically applicable to different environments.

Fourth, the divine law, that is, the written law of God, the Bible. Its significance lies in making up for the deficiency of personal law.

To sum up, in Aquinas' political thought, God's reason and ideal are obviously above everything else, and God is the leader of the whole universe.

Some people may question, is there really a God? Therefore, regarding the existence of God, on the one hand, Thomas believes that the existence and essence of God are absolutely the same, and the essence of God already contains existence. On the other hand, he admits that the existence of God is not a direct and self-evident truth for human reason, so it needs to be proved. Based on this, Thomas put forward five proofs about the existence of God in the Encyclopedia of Theology:

1. "Demonstrate from the movement or change of things". Aquinas believes that all moving things are always driven by other things, so any movement is caused by another movement before it, and the first driver is God.

2. "Discuss the existence of God from the essence of dynamic reasons". Aquinas believes that in the phenomenal world, people have discovered an order with dynamic reasons. Among the dynamic reasons, if there is no first dynamic reason, there is no intermediate reason and no final result. Therefore, there must be an initial motive, and this initial motive is God.

3. "Prove the existence of God from the possibility and inevitability". The existence and non-existence of all things in the world is a possibility and a necessity. One thing has its own inevitability, rather than relying on other things to obtain inevitability. This thing is God.

4. "Prove the existence of God from the authenticity level found in things". Aquinas asserted that there must be something in the world as the reason for the existence, goodness and other perfection of everything in the world. This reason is for God.

5. "Prove the existence of God from the purpose of the world". Everything in the world moves with a purpose, and its activities always follow the same path in order to get the best results. Therefore, Aquinas believes that there must be a wisdom, and all natural things depend on it to point to their purposes. This is God.

Thomas Aquinas is one of the earliest advocates of natural theology and the founder of Thomas School of Philosophy, which has long been an important foundation of Catholic philosophy. The most famous work he wrote is The Complete Book of Theology. The Catholic Church considered him the greatest theologian in history and listed him as one of the 33 church saints.

As a master of scholasticism, Aquinas' political thought can be said to be theocracy, and its core is that God is above everything else and everything serves God. He advocated that politics belongs to religion, secular belongs to the church, and the emperor is ordered by the Pope. Its essence is to safeguard the interests of feudal religious theology and the church.

Aquinas' theism played a role in maintaining social stability at that time. He unified people's thoughts with God and attributed them to God. Now it may be an absurd retrogression, but referring to China at the same time, the concept of the son of heaven is also deeply rooted, and as a product of a specific period, it will play a role in a specific period.