Modern humanism has taught us to think that the 'real is the rational and the rational is the real'. What is real is what you see. What you can't see, either with the naked eye, microscope or telescope, does not exist.
The early Church Fathers and the Reformers had another way of seeing reality, which cannot simply be dismissed as primitive. The universe has two aspects, visible and invisible. The creative decree and acts of God hold together in unity visible and invisible reality. By his mighty power everything exists purposefully every second of every day.
The Nicene Creed of 381 begins: 'I believe in one God the Father Almighty, Maker of heaven and earth and of all things visible and invisible'.