i believe Theism explains best our existence, and i believe, the God that revealed himself in the bible, is the creator of all that exists. What are my reasons to believe so ?
1. The universe had a beginning, therefore a cause. Since beyond our universe, there was no time, no space, and no matter, that cause must be timeless, beginningless, eternal, spaceless, transcendent, invisible, personal, incredibly powerful. That description fits best to the God of the bible.
2. The universe is finely tuned to permit life on our planet. Over 120 fine tune constants are know up to know, and as more time pasts, more are discovered. This might be due to chance, to physical need, or to design. Chance is a very bad explanation. Some advocate a Multiverse. But to have just one life permitting universe, you need 1 to 10^500 attempts to get it done. Thats a 1 with 500 zeros. If we put it in comparison, that in our universe, there exist around 10^80 atoms, this shows how improbable it is, that a Multiverse could explain finetuning. It could not be by physical need, since if so, why are there many planets, which are not life permitting, but our is ? So its best explained by design. Our earth/solar/moon system is a very strong evidence. Our solar system is embedded at the right position in our galaxy, neither too close, nor too far from the center of the galaxy. Its also the only location, which alouds us to explore the universe, In a other location, and we would not see more than stellar clouds. The earth has the right distance from the sun, and so has the moon from the earth. The size of the moon, and the earth, is the right one. Our planet has the needed minerals, and water. It has the right atmosphere, and a ozon protecting mantle. Jupiter attracts all asteroids , avoiding these to fall to the earth, and make life impossible. The earths magnetic field protects us from the deadly rays of the sun. The velocity of rotation of the earth is just right. And so is the axial tilt of the earth. Beside this, volcano activities, earth quakes, the size of the crust of the earth, and more over 70 different paramenters must be just right. To believe, all these are just right by chance, needs a big leap of faith. This is indeed maibe the strongest argument for theism.
3. Life. Abiogenesis has not been able to explain the existence of life on earth. Science cannot explain it. There are strong reasons to believe, a natural origin is not probable, and a bad explanation. First of all, why whould dead rocks need to evolve, to create life ? Secondly, just one living cell is more complex than the most complex machine created by man. A living cell is irreducible complex. All parts must be on place, making a gradual evolution not possible.
Even the simplest cell needs DNA , which is a information carrier. Information is always created by a mind. There i no natural mechanism known to man, to create information. Information is by essence spiritual, and not physical. There is no bridge to cross the gulf from material to spiritual. Even through millions of years of evolution. Its not possible. Add to this the moral argument, experience of miracles, the testimony of the bible, and you have a nice case of theism.