The truth of everything is related to science; some things haven't been explained or understood yet, and that is why we call them myths, but they will be explained someday in the future, and then, the things we believe today to be myths, will be scientifically proven. Let me give you some examples to explain this better. Electricity for example; can we grab electricity itself? When we plug the TV, can we see electricity going from the TV through the cord, to the outlet? No, but we know electricity is there because the TV turns on. Today electricity is proven to exist and work, but imagine if we showed this to a person that has no knowledge about electricity. This person cannot see electricity going trough the cord, and cannot touch electricity, so how does the TV turns on? It must be by some divine being right? It is the same with us, human beings. We have an energy inside us, which I call the human soul. We don't see that energy, we cannot touch it, but we do move, and talk, and have electric impulses, so where does that energy come from, where is it connected to? Today, the human soul is still something mystical, but in the future, when we gain more knowledge, it won't be a myth anymore, it will be proven by science. Fire is another example. When man first discovered fire, he thought is was something made from god, a divine work. Today we can scientifically explain fire, something that nobody was ever able to explain when fire was first discovered. .
Let's go back to the Greek myths and Greek Gods. All those myths have a scientific explanation, which we don't know today. The explanation may be that it is not true at all, or that it is true. What we need to understand, is that the people in that time had a lot less knowledge than we have today. When they saw somebody that had more knowledge and showed them things they never saw before, they call him or her a God. That God might have been somebody from a more advanced place, or even from another world.