Religious Medieval philosophers tried to use reason to do three things: to support their belief in a god, to prove their belief in a god, and to develop a unified theory of all knowledge, divine and human. They partly succeeded in the first of these aims, and failed in the other two.
We must remember the context of Medieval times. Tradition was very important. Philosophy was considered an art (or a craft in today’s language). Philosophers were expected to first learn existing knowledge, and only then start to develop their own ideas.
Medieval Christian, Islamic and Jewish philosophers each faced different problems in trying to reconcile their faith with reason and logic. In Part 1 of this article, I described how ten of them attempted to do this. In this second part, I examine why they failed to do so.
Medieval Appeals to Authority: Divine, Rational and Human
In theory, Western Medieval philosophers gave different weight to different sources of information.
The authority of God was the strongest argument: this trumped all counter arguments.
Next strongest was an argument based on reason.
Next came an argument based on human authority.
- The strength of this argument depended on the credibility of the source: ‘Aristotle has said…’ was a considerably stronger argument than ‘My slave’s daughter has said…’.
- If the source had credibility, an appeal to human authority stood as a valid argument-unless or until it was contradicted using reason.
In practice, these distinctions were often blurred. A religious philosopher could not directly challenge God’s word (level 1), but he could assert that a human authority (level 3) had misinterpreted God’s word. He could thus challenge the human authority, using reason (level 2).
(Martin, 1996: 16-20)
Religious Restrictions on Medieval Philosophers
Medieval Christian philosophers operated within a political and legal framework strongly influenced by Christian theology.
Christian theology was in turn subservient to the direct authority and approval of the Pope and various Councils, with the Pope claiming to be able to infallibly interpret the word of God.
Medieval Islamic philosophers, in theory, had more freedom.
Islamic theology was merely the thought of human theologians, who are fallible. Philosophers were therefore free to contradict Islamic theologians, assuming they could rationally defend their arguments.
In practice, they had to consider the impact of their works on the powerful and often-conservative Islamic clergy.
- For example, Ibn Rushd (Averroes) argued that the ‘creation’ of the universe means its continuous transformation.
- However, he proposed that this argument be restricted to those educationally qualified to understand it, leaving most Muslims with more simple beliefs that would not challenge their faith in Islam.
Ultimately, philosophers could face charges of heresy under Islamic law.
(Hourani, 1987: 567)
Medieval Jewish philosophy existed largely within the context of the Islamic and Christian civilizations in which Jews lived.
(Smart, 1998: 183-184).
Did They Succeed in Creating a Unified Theory of All Knowledge?
They failed to do this.
Medieval Christian philosophers faced the following problems:
The Augustinian project sought to synthesize all knowledge by rationally reconciling Neoplatonism with Christian belief.
- Some beliefs were hard to reconcile, such as Neoplatonism’s distrust of the body (versus the incarnation of Christ), and the Neoplatonic transmigration of the Soul.
- The project thus ran the risk of stagnating into fideism, with Pagan arguments being rejected purely on the basis of faith, ignoring reason.
- In countering this risk, Augustinians found it useful to use Aristotelian logic (available via the translations of Boethius).
- Aristotle was thus incorporated into Christian tradition as ‘an authority’, whose citing gave force to Christian arguments.
Later, Aristotle’s metaphysics – with, for example, its eternity theory contradicting creationism – reached Christians via Ibn Rushd (Averroes).
- Aristotle’s logic, already cited by Christian philosophers, was naturally more consistent with his own metaphysics than with Christian theology.
- Christian philosophers now had the dilemma of rejecting Aristotle’s metaphysics, without undermining his ‘authority’.
- Aquinas attempted this, partly by arguing that some issues can only be decided by Divine revelation, but his compromise was rejected (by both conservative Augustinian Christians and strict Aristotelians).
In the University structures, this eventually led to a split between the study of Divinity and the study of the Arts-exactly the opposite of the purpose of the original ‘unified synthesis’ project.
(Martin, 1996: 57-117; Moran, 2003: 9-11; Feldman 1987: 408)
Medieval Islamic philosophers faced the following problems:
Orthodox Islam found Greek metaphysics useful in countering anthropomorphic ideas of God.
However, Al-Ghazali in particular exposed contradictions between Islamic faith and philosophy. These included the eternity of the cosmos, the claim that this is consistent with creation, God’s knowledge of universals and particulars, and the denial of the resurrection of the body.
Ibn Rushd (Averroes), Al-Ghazali’s clearest critic, was charged with heresy – or of arguing that there were two different truths, based respectively on faith and reason; a charge he denied.
Sufism-a mystical offshoot of Orthodox Islam – was more consistent with Neoplatonism, but Sufism was not the main strand of Islam. Also, it developed partly in reaction against the rationalism of philosophy.
(Smart, 1998: 168-173, 181; Martin, 1996: 116)
Medieval Jewish philosophers faced the following problems:
- Medieval Jewish philosophy existed largely within the context of the Islamic and Christian civilizations in which Jews lived.
- It only seriously emerged in the 9th century, in the context of Islamic philosophy, and then flourished in the 12th century with Ben Maimon.
- It faced broadly the same challenges as Islamic and Christian philosophy in seeking to reconcile faith and reason.
(Smart, 1998: 183-184)
Did They Succeed in Proving Their Belief in a God?
They did not succeed in this.
This is best illustrated by examining Aquinas’s attempt to use reason to prove the existence of the Christian God.
I will deal in another article with the question of whether his Five Ways arguments are valid (and I will argue that they aren’t).
But, even if they were valid, all that they could prove only that an undefined something might exist. He ends each by simply assuming that this something ‘is what everyone calls God’.
Also, the five Ways are in any case only half of Aquinas’s attempt to prove the existence of God. His self-imposed challenge is to rationally answer two counter-arguments, not one. These are:
- That the existence of evil is inconsistent with God.
- That nature can be explained without reference to God.
His five Ways address only the second argument.
To the first he simply refers to the human authority of Augustine. His sole argument is that, ‘as Augustine says’, God is supremely good so He would not allow evil unless He could bring good from it.
The circular logic of this half of his proof fatally undermines whatever limited rational credibility the five Ways may have.
(Aquinas, Summa Theologiae, 1a.2.3)
Did They Succeed in Supporting Their Belief in a God?
They partly succeeded in this, by selectively using parts of Greek philosophy.
Aristotelian logic, and ideas such as the first unmoved mover, could be used to help to support (already-existing) beliefs in a god.
The ‘other-worldliness’ of Neoplatonism could be used to support Christian mysticism, Islamic Sufism and Jewish Kabbalah (although the latter two developed partly in reaction against the rationalism of theistic philosophy).
One illustration of their success in supporting mainstream Christianity is the painting The Triumph of Saint Thomas (1471) by Benozzo Gozzoli (1420-1497), now in the Musée du Louvre, Paris.
The top panel shows Christ, flanked by Paul, Moses and the four Evangelists. Christ announces: ‘You have written well about Me, Thomas.’ The centre panel shows Aquinas, with Aristotle and Plato showing him their work. Ibn Rushd (Averroes) lies at their feet, symbolizing the defeat of his arguments by Aquinas. The bottom Panel shows Pope Sixtus IV, flanked by various clergymen.
Aquinas, Thomas. Summa Theologiae. In McDermott, Timothy, 1993. Aquinas: Selected Philosophical Writings. London: Oxford World Classics.
Feldman, Seymour, 1987. Aristotelianism, in The Encyclopedia of Religion. Ed. Mercia Eliade. New York: MacMillan Publishing Company.
Hourani, George F., 1987. Ibn Rushd, in The Encyclopedia of Religion. Ed. Mercia Eliade. New York: MacMillan Publishing Company.
Martin, Christoper J.F., 1996. An Introduction to Medieval Philosphy. Edinburgh University Press.
Moran, Dermot, 2003. Medieval Philosophy. In Bachelor of Arts, Philosophy 1. Dublin: Oscail, Dublin City University.
Smart, Ninian, 1998. World Philosophies. London: Routledge.