Augustinianism is the philosophical and theological system of Augustine of Hippo and its subsequent development by other thinkers, notably Boethius, Anselm of Canterbury and Bonaventure. Among Augustine's most important works are The City of God, , and Confessions.
Originally, Augustinianism developed in opposition to Pelagianism; it was widespread in medieval western philosophy until the arrival of Thomism and Aristotelianism.
Plato and Plotinus influenced Augustine in many ways, and he is considered a Neoplatonic philosopher.The Augustinian theodicy and other Augustinian doctrines such as the divine illumination and the invisible church show a strong Platonic influence.
Pope Benedict XVI cautioned that all of the Western Church teaching leads to him:
View of humanity
"Augustine considered the human race as a compact mass, a collective body, responsible in its unity and solidarity. Carrying out his system in all its logical consequences, he laid down the following rigid proposition as his doctrine: 'As all men have sinned in Adam; they are subject to the condemnation of God on account of this hereditary sin and the guilt thereof'"
According to Augustine, even the world and corporeal entities, being fruits of divine love, have their value and meaning, while the some Platonists tended instead to devalue them. This attempt to place history and earthly existence within a heavenly perspective, where even evil finds explanation in some way, always remained at the center of its philosophical concerns.
Ethics
These are the most important values for an Augustinian.
Love
Interiority
Humility
Devotion to Study and the pursuit of Wisdom
Freedom
Community
Common good
Humble and generous service
Friendship
Prayer
Meta-ethics
Augustine offered the Divine command theory, a theory which proposes that an action's status as morally good is equivalent to whether it is commanded by God. Augustine's theory began by casting ethics as the pursuit of the supreme good, which delivers human happiness, Augustine argued that to achieve this happiness, humans must love objects that are worthy of human love in the correct manner; this requires humans to love God, which then allows them to correctly love that which is worthy of being loved. Augustine's ethics proposed that the act of loving God enables humans to properly orient their loves, leading to human happiness and fulfilment.
Just war
The Just war theory is a doctrine that ensure war is morally justifiable through a series of criteria, all of which must be met for a war to be considered just. In Romans 13:4 Augustine claims that, while individuals should not resort immediately to violence, God has given the sword to government for good reason. Augustine argues that Christians, as part of a government, need not be ashamed of protecting peace and punishing wickedness when forced to do so by a government. Augustine asserted that this was a personal, philosophical stance: "What is here required is not a bodily action, but an inward disposition. The sacred seat of virtue is the heart."
Happiness
Augustine's ethics is that of ancient eudaimonism, but he defers happiness to the afterlife and blames the ancient ethicists saying that their arrogant conviction resulting from their ignorance of the fallen condition of humanity that they could reach happiness in this life by philosophical endeavor, Augustine takes it as axiomatic that happiness is the ultimate goal pursued by all human beings. For Augustine Happiness or the good life is brought about by the possession of the greatest good in nature that humans can attain and that one cannot lose against one's will.
Epistemology
Augustine emphasised the role of divine illumination in our thought, saying that "The mind needs to be enlightened by light from outside itself, so that it can participate in truth, because it is not itself the nature of truth. You will light my lamp, Lord,"
For Augustine, God does not give us certain information, but rather gives us insight into the truth of the information we received for ourselves.
If we both see that what you say is true, and we both see that what I say is true, then where do we see that? Not I in you, nor you in me, but both of us in that unalterable truth that is above our minds.