Why is it usual to describe St. Thomas' political theory as reflecting a 'Christian Aristotelianism'?
Context
Before Aquinas, the church’s political philosophy was largely based on Neoplatonism. The Church was considered to have priority access to ‘God’, and therefore truth and power. Jesus said that those “who mix in the world” should “live as if they were not engrossed in it, for the present phase of things is passing away”. Circa 200CE, Tertullian argued that as “Christ rejected an earthly Kingdom,” “secular powers.. are not merely alien from, but hostile to, God.” In 494CE Pope Gelasius formulated the 'two swords’ theory of regnum and sacerdotum (politics and religion), where politics was the 'bloody’ sword necessary to allow the good work of the Church. In turn, the writing of Augustine (354-430CE, see previous tutorial) was particularly important, and this relates to his belief (from the Biblical St. Paul) in the 'negative naturalness’ of politics. We live in a fallen, sinful world, so require a strong government to suppress our corrupt and wicked ways. Politics is neither good nor natural, and is not necessary in Heaven. Indeed, Augustine sees Heaven and Earth as mutually exclusive spheres, and so a person must choose between satisfaction in one existence or the other. In particular, tyranny is a punishment for a sinful populace from God, and so (unless the tyrant disobeys God’s clear will) it should not be resisted.
Aristotle
Aristotle (384-430BCE) was an important thinker in Ancient Greece. He sought to base truth not in the eternal forms of Plato, but the study of physical being. (Therefore pointing down in Raphael’s 'School of Athens’). The universe is the expanded analogy of the polis, with logical and not devilish laws. He had a teleological outlook, which argues that everything has a telos (purpose). This telos is achieved through an ergon (unique task) and leads to eudaimonia (well-being). Aristotle’s philosophy is based on reason and intellect, obviously lacking a Christian after-life, so his theory has a focus on the Earthly life antithetical to Augustine. As for politics, Aristotle’s 'Politics’ points out that “Man is by nature a political animal”, i.e. politics is natural and therefore good. In turn, man should be (ideally) ruled by a philosopher king, embodied by some neo-Aristotelian Christian thinkers as the Pope.
However, much of this output was lost to the Western world in the Dark Ages, surviving in Islamic work due to thinkers such as Averroes (Abū 'l-Walīd Muḥammad ibn Aḥmad ibn Rushd). In 1245, Aquinas was introduced to Aristotle by his lecturer Albertus Magnus in Paris, and became part of a movement to resuscitate his philosophy. This was considered undesirable by Church elders, due to the dual taints of Aristotle’s paganism and the Islamic source of many of the translations. Also, the eternity of Aristotle’s world interfered with the principle of a Christian creation. However, Aquinas (amongst others), persevered.
Aquinas
From these two bases of existing Christian philosophy and Aristotelianism, the theologian Aquinas forged a synthesis to reconcile the seemingly opposed principles of Heaven and Earth; Christianity and politics. He follows Aristotle in seeing politics as naturally positive; a compliment to the Church rather than its enemy. In other words, a “Christian politician” should be not be the logical impossibility inferred by Augustine. Aquinas also agrees with Aristotle’s view of a rational, humane and ordered world; but believed that life transcended this mortal coil, seeing the Christian Heaven as a perfect version of a broadly positive Earth. This adds the Christian virtues of 'faith, hope and charity’ to Aristotle’s 'prudence, justice, fortitude and temperance’. Aquinas said that “Grace does not do away with reason but perfects it”, as something of a proto-Christian scientist (NOT Christian Scientism). In other words, 'faith completes what reason begins’. This is obviously in great contrast to the thinking of Augustine, arguing that politics is not sordid but merely incomplete in its spiritual dimension.
Aquinas does not have quite the interest of Aristotle of clearly defining “goodness”, but does say that we should seek the 'common good’. This leads neatly into the rest of his political philosophy, but first his “laws” should be considered. As a Christian, he begins with 'Eternal’ law, i.e. the rules of Aristotle’s ordered universe adapted to place God at the helm. This pervades all other law, but due to the very nature of God’s greatness, cannot possibly be directly perceived by humans. However, what we can derive is 'Natural’ law, a general body of directions for all humans (and indeed animals). This, in turn, is too vague for everyday application, so is distilled into 'Human’ or civil law, i.e. our political codes and regulations. Each step has been constructed from the previous, and is so subservient to it. Therefore, a human law which contradicts natural law is not law at all, which becomes important when considering political obedience. Also, these three are exclusively concerned with exterior actions. Aquinas describes a “Divine” law running alongside, which is Scripture-derived morality governing our inner selves. Indeed, he denies that human law can have any obligation-imposing authority over matters which concern the inner life of the will. In such matters we are subject only to God. Aquinas argued that “we are all, by nature, on a par”, in a manner that would be greatly expanded by Locke.
These laws are the basis for a number of areas in Aquinas’ political philosophy. For example, Aquinas was a moderate Papalist, as his understanding of Divine law renders the Pope superior to secular leaders. However, unfortunately for an increasingly politically-motivated Papacy, he admitted the value of secular power. This tension would be observed in the religious wars of later centuries as the practical power of the Papacy was questioned by critical kings, a question which continued to reverberate in Locke’s time.
This moderate Papalism informs Aquinas’ ideology, seeing kings as the superior form of leadership. Much as a single God most effectively rules the universe, a king will make the best use of political power in his lands. The rule of the many, as it was understood in the thirteenth century, would only lead to tyranny, the worst form of government. However, the king should not be all powerful. Firstly, he was subservient to God, and had to obey divine law. While not to the level seen later in Locke, Aquinas allowed a greater degree of tyrannicide than Augustine. He applied it conservatively with many caveats, but accepted that a Christian’s duty to obey authority was conditional on the Christian application of that authority.
Another major deviation from accepted thinking was the position of government in society. Their function is their purpose, to allow the common good of the people. Far from Augustine’s prescription of suppressive, malevolent forces; Aquinas’ governments would benignly lead its citizens towards a Christian life. This would later be seen in the contrast between Hobbes’ and Locke’s expected functions of political leadership. Aquinas called tyranny the worst form of government as it was least likely to fulfil the common good of the people, or be religiously positive. If man is indeed on a par with his fellow man, then tyranny is inconceivable.
In summary, Aquinas’ political thinking does broadly reflect a 'Christian Aristotelianism’. As with any synthesis, it has to adapt the two sources, but remains mainly true to both foundations.