In the early 20th century, a group of thinkers looked back to the medieval philosopher Thomas Aquinas to find answers for modern problems. This movement, known as Neo-Scholasticism, wasn't about dusty, irrelevant ideas. It was a robust attempt to ground philosophy in reality, pushing back against the rising tide of subjectivism. Kurt F. Reinhardt was a key voice in this revival.

He argued for a "perennial philosophy." This doesn't just mean old; it means enduring. Reinhardt believed certain fundamental truths about existence don't change with the times. For him, the most important of these was the simple fact that a real world exists, and it doesn't depend on our minds to be there.

Reinhardt's core position is Ontological Realism. The term sounds complex, but the idea is straightforward: being, or reality, has priority over thinking. There is an objective world of things that exists whether we perceive it, think about it, or even know it's there. This stands in stark contrast to Subjective Idealism, the view that reality is fundamentally a construction of the mind or consciousness.

This leads directly to the correspondence theory of truth. In Neo-Scholastic thought, a statement is true if it corresponds to objective reality. The thought in your mind, "that is a tree," is true only if there is an actual tree in the world that your thought accurately describes. Truth isn't something we invent; it's a relationship of conformity between the intellect and the thing itself. The mind doesn't create truth, it discovers it.

Reinhardt, like other Neo-Scholastics, identified a critical wrong turn in Western philosophy. He pinpointed the Cartesian Turn as the moment the focus shifted from objective being to subjective thought. When René Descartes famously concluded, "I think, therefore I am," he established his own consciousness as the starting point for all certainty. From a Neo-Scholastic perspective, this was a profound error.

It made the human mind the measure of all things and opened the door to skepticism about the external world. If all you can be certain of is your own mind, how can you ever be sure about anything outside of it? This inward turn ultimately led to thinkers like Immanuel Kant, who argued that we can never know things "in themselves," only as they appear to us, structured by the categories of our own minds.

Reinhardt's project was to reverse this. He argued for a return to a lived, ontological realism. This isn't just a logical exercise; it's about embracing the totality of human experience. We don't experience ourselves as isolated minds building a world from scratch. We experience ourselves as beings in a world that was here before us and will be here after us. For Reinhardt, this common-sense starting point is also the most philosophically sound one.