Bonaventure (John of Fidanza) developed a synthesis of philosophy and theology in which Neoplatonic doctrines are transformed by a Christian framework. Though often remembered for his denunciations of Aristotle, Bonaventure’s thought includes some Aristotelian elements. His criticisms of Aristotle were motivated chiefly by his concern that various colleagues, more impressed by Aristotle’s work than they had reason to be, were philosophizing with the blindness of pagans instead of the wisdom of Christians.
To Bonaventure, the ultimate goal of human life is happiness, and happiness comes from union with God in the afterlife. If one forgets this goal when philosophizing, the higher purpose of the discipline is frustrated. Philosophical studies can indeed help in attaining happiness, but only if pursued with humility and as part of a morally upright life. In the grander scheme of things, the ascent of the heart is more important than the ascent of the mind.
Bonaventure’s later works consistently emphasize that all creation emanates from, reflects and returns to its source. Because the meaning of human life can be understood only from this wider perspective, the general aim is to show an integrated whole hierarchically ordered to God. The structure and symbolism favoured by Bonaventure reflect mystical elements as well. The world, no less than a book, reveals its creator: all visible things represent a higher reality. The theologian must use symbols to reveal this deeper meaning. He must teach especially of Christ, through whom God creates everything that exists and who is the sole medium by which we can return to our creator.
Bonaventure’s theory of illumination aims to account for the certitude of human knowledge. He argues that there can be no certain knowledge unless the knower is infallible and what is known cannot change. Because the human mind cannot be entirely infallible through its own power, it needs the cooperation of God, even as it needs God as the source of immutable truths. Sense experience does not suffice, for it cannot reveal that what is true could not possibly be otherwise; so, in Bonaventure’s view, the human mind attains certainty about the world only when it understands it in light of the ‘eternal reasons’ or divine ideas. This illumination from God, while necessary for certainty, ordinarily proceeds without a person’s being conscious of it.