“It is possible to demonstrate God’s existence, although not a priori, yet a posteriori from some work of His more surely known to us.”
- 1225 – March 7, 1274
- Born in the Kingdom of Sicily (Italy)
- Theologian, philosopher
- A representative figure of scholasticism, who systematized the relationship between the doctrines of the Catholic Church and reason through his masterpiece, the Summa Theologica
Quote
“It is possible to demonstrate God’s existence, although not a priori, yet a posteriori from some work of His more surely known to us.”
Explanation
In this quote, Thomas Aquinas argues that the existence of God can be demonstrated not through a priori reasoning—which is based on self-evident principles—but through a posteriori evidence, meaning observations from the natural world and experience. For Aquinas, the existence of God is not something that can be deduced purely by logical necessity or intuition. Instead, he contends that we can infer God’s existence by examining the world around us, which provides clear indications of a higher cause or intelligent design. These effects, which are more familiar and directly known to us, point towards an ultimate first cause—God.
Aquinas’s approach reflects his efforts to bridge theology and philosophy, particularly by incorporating Aristotelian logic into Christian thought. He believed that while faith is important, the natural world also provides sufficient evidence of God’s existence that can be understood through reason. His famous “Five Ways” are a series of arguments that attempt to demonstrate God’s existence by looking at observable realities like motion, causation, contingency, degrees of perfection, and teleological order (purpose in nature). In these arguments, Aquinas uses empirical observations as a foundation for rational arguments, showing that understanding God does not rely solely on revelation but can also involve the logical interpretation of what we see in the world.
In the modern context, this approach resonates with those who seek a rational basis for spiritual belief. For instance, many people today find evidence of a higher power in the complexity and order of the universe, the fine-tuning of the cosmos, or the intricate processes of life. Aquinas’s emphasis on an a posteriori approach encourages a balanced perspective, where both reason and observation serve as tools for understanding deeper existential questions. His argument is a reminder that while some aspects of spirituality are beyond human comprehension, the evidence of the divine may be accessible through the careful and thoughtful exploration of the world we experience.
