I use simple science to evidence the existence of the gods. Richard Dawkins is actually responsible for the scientific breakthrough that proved theism.
See, Dawkins came up with this model of the “meme” and the field of memetics. The core concept is that ideas spread through the human population like germs. They reproduce, mutate, and some ideas are fitter than others. In other words, they’re subject to evolutionary pressures. They behave just like living organisms. They grow and change in order to secure their own survival and dominance in the ecosystem.
So if ideas are alive, and some ideas are the gods, then the gods are alive as ideas. They act to secure their own existence. Take the cultural genocide enacted by Christians on the rest of the world during colonisation. This is easily explained by an idea that wants to be the only god anyone believes in, and which can act to this end. Because the strains of the meme which propagate the most are blind and hateful loyalty. The Christian god really is alive and he really does control Christians. He’s an idea, and he wants to be in everyone’s head.
Every god worshipped by some religion, no matter how small, is real. They are made real by worship.