This is a quite interesting question.
What can I say? I used to be an atheist when I was 12 and, by between 19 and 20, I turned into deist (panendeist to be more specific, thanks to hinduism).
Some people tend to ask me why I believe in a supreme intelligence (A.K.A a god/goddess or whatever) and I tell them I believe in that because, to my reasoning and subjective experience, is impossible to me to accept the idea that this universe came from a random process or by chance and must have a purpose or a meaning, even Roger Penrose (who is an atheist) believes that the universe must have a purpose.
The universe is freakishly fine tuned for the existence of intelligent life, and some atheists claim that was luck, and taking in consideration the possibility of a multiverse out there, I don't believe that the multiverse allows the existence of life-permitting and life-prohibiting universes at the same time and not being paradoxical, even I said that to a Computer Scientist (He has a PhD, and I assume he's an atheist or agnostic) and he realized that my reasoning to believe in my multiverse idea was entirely rational, and he was speechless. God! I felt really great after that.
Even accepting the "atheistic" multiverse, I don't accept that the configuration that allows life as we know it is random because, by assuming that must be there an infinite sets of configurations, sooner or later, must be there another set that allows intelligent life completely different than our universe's set (just imagine that our universe is the configuration A, but B, C, D, E and so on are not fine tuned but at least in the infinite probabilities and possibilities must be there another set like A but with different configuration, calling it B22C44G19, as an example), life must exist in other configurations, but no. Actually, Luke A. Barnes has shown to his audience in a conference that this configuration is the best and only one that allows intelligent life, and he's a christian astrophysicist by the way.
This configuration is the only one that allows intelligent life from an infinite set of configurations. I don't care if there are other universes with intelligent life, all of them share the same physical attributes, which are completely different to variables. Let’s clarify, by comparing the laws of nature with the solar systems that have planets with life because the attributes of life in this universe are really flexible and variable, but the physical constants are not like that, and life are tied to these physical constants. The universe doesn't care if the star is small o really big, there are laws that say the goldilocks zone must be proportional to the mass or the brightness of the star, which is a variable tied to laws of nature, and such laws and physical constants are NOT variable, they’re immutable, that's why they're constants.
The only possibility that works perfectly is the idea of a Supreme Intelligence that wanted to make it that way, and that's why I believe the universe must have a purpose. What's the purpose? I don't know and I don't care, but I think that there must be some purpose/meaning.
The other reason I believe in a Supreme Intelligence is that the universe is extraordinarily comprehensible in the mathematical language. I talked to many mathematicians and I investigated deeply about it, and most of them are platonists, because they hold that math is a discovery, and not an invention as many atheists claim, even Penrose is a platonist. The reason that they believe that mathematics is a discovery it's because they describe the behaviour of the universe perfectly, without any error range. Just name one human invention that is perfect in all senses and without error range. Is there any? Obviously you can’t because there's not. Even there are animals that understand basic arithmetics, so... did they invent arithmetic or discover it because their brains are capable of comprehending complex abstractions like numbers and getting to the same conclusions as humans did? The invention proposal doesn't sound really rational, right? Many mathematicians believe that mathematics are God's Thoughts and I think that makes more sense than accepting the idea of human invention. Even if there are aliens out there, they must use math to travel to space and to create machines and so on... the invention idea is getting smaller and smaller.
The other reason is about the laws of nature. Are Laws of Nature natural? it’s a weird question I must admit it but I’ll explain it. Imagine an Apple, that apple is a fruit which has DNA in it, and the DNA is constituted by molecules which are constituted by atoms and which are constituted by quarks, and so on and so on. With all those characteristics, that apple is made of matter and that fruit is influenced by laws of nature such as gravity, laws of thermodynamics, etc. Am I right? but what about energy? Energy is influenced by the Laws of Nature as well and we know that energy can turn into Matter and vice versa. So… energy and Matter are physical, right? So… That apple is physical at all, and by being physical we could say that that apple is natural because it is ruled by these laws and so as you and me and a computer, and anything else. So, in the point of view of naturalism, that apple is natural and is affected by time, occupies a location in space, is predated and influenced by the Laws of Nature… The same thing happens with the universe. The universe is natural because of these laws and it was created from nothing (Apparently), and all of these thanks to these laws.
But… What about the Laws of Nature? Are they made of matter? No… Are they made of energy? No… So, Laws of Nature are not physical, and by being not physical, They’re Timeless and spaceless. So, we could say that Laws of Nature are not physical, they’re Timeless and spaceless, predate the universe, act on the physical, they created the universe from nothing (apparently)… So, at what moment are Laws of Nature natural? All these characteristics are implying that there’s nothing behind them, there's nothing that acts on them (not even the universe acts on them), they're eternal (apparently)… By following the characteristics of the apple, Laws of nature are supernatural and they have a naturalistic effect on the universe. That's the principal reason that I think that naturalism fails because it can’t explain that or the naturalists don't want to deal with that peculiarity; that’s where naturalism fails, at least the Metaphysical Naturalism.
If You want a better picture of it… Imagine a Bubble floating in the total Darkness, the Real Nothingness. That bubble is the Laws of Nature. Inside that bubble the universe, the multiverse, life and death and anything else are happening inside that bubble. That bubble affects its own interior, but nothing inside of it affects that bubble, while nothing outside that bubble acts on it, unless it’s that what it appears. Laws of Nature are just they, like God is just it. And for that reason, that’s Why I believe that the universe has a purpose, a point, a meaning, regardless of whether a god exists or not. I don’t know if you think the same, but I want to know your opinion.
When we learn more about the universe and analyse it, we realize that the laws of nature and mathematics are going from realistic to imaginary, and the universe becomes more and more abstract and supernatural. The universe is getting weirder, so alien to us and to any human expectation. Then why should we reject the idea of a deity? to me, considering the concept of a god/gods should be taken seriously. Not saying that we should believe, but being humble to the idea.
Those are the reasons I believe in a Supreme Intelligence, you can correct me if you want, or you can take some ideas from here to increase your deism. If I’ve offended someone, I apologize. Those are my reflections, you can help me to improve them or vice versa. Hope you like it.
Wish you the best. Thanks for reading.