As an atheist I shall answer thusly:
First, from the perspective of a theist.
I don't remember the exact quote(s), but as far as I know, there are numerous passages about how only those who accept Jesus can truly understand what God and Jesus is all about. So atheists cannot understand God and therefore cannot use arguements to refute things they do not understand nor comprehend. That is a point you could make, but I can point out a problem or two with that arguement.
While god might not be all powerful, all knowing, nor all good, that doesn't mean that god can't do things that we cannot comprehend, fathom, or even contemplate. Being all powerful means being able to do everything. But since god is not all powerful (sorry, he isn't and I won't say he is), that doesn't prevent him from doing powerful things, like raising the dead. This goes for being all knowing and all good as well. He is not those things, but that doesn't mean God is not able to know amazing things, or do great things.
There is the teleological argument of course which states that all that exists has been designed. As it was created, and since it was created and came into existence, then something had to cause that beginning and original existence. Since nature is one of these designs, it only logical to conlude that God is the force behind that creation and he is the creator (because anything designed has to have a designer, otherwise, how was designed? By nothing?)
This is evident in nature. We see fibanochi's sequence in a vast majority of plants and animals, from their shells to the way trees grow in the spring.
This design is also evident in the way the rest of the universe looks. Why are flowers so pleasing to the human eye? Why need beauty instead of just biological functions? Why do bees need an attractive flower?
Or perhaps how only one planet in the entire solar system is suited for live in a percentage of it's area? Very few other planets are seen that can support life in the universe, if any.
The way that animals and plants are so complex is proof that they could not have come into existence on their own. Even through evolution, DNA, polyploidy, and the logical design of animals and plants with such an intuitive sense of the best way a plant or animal works is proof that God exists.
Lastly, humans. We are the only species on earth that can think the way we do, act the way we do, and do the things we do. Why are we special? Because that is what God intended of us.
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Third:
Higher power of what? Well lets start with the Abrahamic God. Many have claimed that he is outside our reality, yet he may act upon it. Which would mean it is impossible to find evidence for or against a higher power ( a god like one) until we can successfully enter the dimension in which this being resides.
However, I can prove that nothing can be all powerful, all knowing, nor all good.. He cannot make himself know more than there is. So either he knows everything but is not all powerful, or he is all powerful, but does not know everything.
But he is not all powerful because he cannot make a rock he cannot lift.
And he is not all knowing because, all knowing means knowing EVERYTHING. Including knowing what it is like to enjoy being evil from knowing that from experience. But god is all good, so he can't know that, which means he is not all knowing.
Even if God were to understand what it feels like to be evil from the perspective of someone else, and hence not ACTUALLY feel that feeling, God is maximal. In other words, better than everyone at everything. Which means he would have to enjoy being evil MORE than anyone in the planet. Not only that, but he would have to know what it feels like from experience to enjoy being the most evil person on the planet, which since he is maximal or all powerful, means he cannot get that from seeing/feeling it through the eyes of another person. That being said, god is not all powerful, so I can't use that argument.
So let's use another. Not using anything from scripture or the bible: If someone is all good, how can they exist at all? Let me explain. All good means no evil. None of it. If God is all good, why would he allow evil to exist? Not talking about Satan or anything, but in general. Of course if god cannot stop evil from being there and he is doing his best, then he is still all good. So let's go a bit further. If God is all good, then that means that anything that god CAN do is good. Well lets look at the world around us shall we (and I won't use scripture here).
God is not all knowing and not all powerful. This means there are things he cannot do. What those things are I don't know, but I don't need to when subjective morals exist. There are times when stealing is wrong and when it could be considered right. There are situations when one simply cannot do the right thing.
Brief story of Winston Churchill if I may: Late in the way, Britain cracked the German code and intercepted a message saying there was going to be a bombing on a city of Britain's. When asked what the evacuation plan was going to be Winston replied, "Nothing. No evacuation." Why one might ask? Because then the Germans will know that we cracked their code and they will get a new one. The war will be longer and more lives will be lost than just one cities worth. Alternatively, saving the people in the city are lives that one KNOWS can be saved. So what do you do? Prolong the war and save innocent people? Or use the code to your advantage to prevent the possibility of more of these bombings to occur? I don't think there is a real answer.
If he isn't all good nor all powerful, then he can be all knowing, but wait....no he can't. Why? Because that would imply that he knows how to be all powerful and all good, but chooses not to, or isn't. How does that prove he isn't all knowing? I'm getting to that.
IF god knows HOW to be all powerful and all good, then he knows he cannot be all powerful and all knowing at the same time (as indicated above). He can be one or the other. But he cannot be all powerful (also as indicated above) therefore he does not know how to become all powerful. Which means there is something he cannot know.
Now in general higher powers:
Well as nothing can be all powerful or all knowing, I don't see why, with enough technology and probably soon-to-be-forbidden-experiments humans could become the "higher" power of another world.
Nothing is stopping an insanely advanced race from doing any of this. In fact, I think this is completely possible to do for a highly advanced civilization. We can already replicate life and can teach robots how to develop personality (kind of), so what is stopping us from being or becoming that higher power?
In all reality, I think the likelihood of a higher power to be possible, but not in the sense of a magical being, just extremely advanced technology.
Here is why. There is no evidence to support it. I know, it's a weak argument, but there has been NOTHING to support it. At all. Ever. In the history of shits and giggles, nothing has EVER happened that implied there was a higher power. But technology, while it hasn't proved nor disproved the existence of a magical higher power, it has given humans the tools and insights to theorize and propose mechanisms and tools, and even begin with making life from literally chemicals. Or robotics. Or synthesizing living cells from scratch. Science has shown that using advanced technology (at this rate, who knows how advanced. could be tomorrow could be 100 years from now) a species could become a "higher power" with the power to do all these things. Which would be incredible.
That is my answer. You asked for it. In all it's long, splendid glory.