If I were to become an atheist...

The great thing about being an atheist is that you don’t actually have to put faith in anything. 

Consciousness is a philosophical idea that was invented and has subsequently been redefined over and over again. Like the more religious terminology “soul”, the meaning of it ultimately depends on which definition you use, and what the individual chooses to believe about it, for which there is no proof. The only thing we can say scientifically about it is that it is directly tied to the presence of a biological, living brain, of sufficient size and processing ability to perceive what might arbitrarily be described as awareness. But it cannot be localized or scientifically defined beyond that. And having a brain in and of itself doesn’t necessarily imply that the owner of this brain is conscious. A person who is alive in the sense that they have a working brain that regulates their biological functions is not conscious if they are put under anesthesia, or in a vegetative state. So it is possible to have a brain and still not be conscious.

Most people would argue that dogs are have consciousness since they seem to be aware of their surroundings. But what about insects, whose brains are significantly smaller? Does a cockroach know he is alive? Or does it just respond to external stimuli because it’s genetically programmed to react in certain ways (instinct). If a dog can “think”, and a cockroach cannot, then at what point in the animal kingdom does a creature go from being conscious to not conscience? If a cockroach is “conscious”, then what about an earthworm? You see how impossible the question becomes the more layers of the onion you start peeling back. That’s why it remains a philosophical concept, and not necessarily something that demands a supernatural interpretation.

Psychology Today (consciousness)

Many of the concepts that you assume require faith (nothing, unconsciousness, non-reason, etc) those are not conditions known to exist. They describe the lack of an existing condition. The development of life and consciousness are natural processes, just as the development of stars and planets are. There are scientific theories (link) that explain how a universe can come from nothing.

Believing in religion to fill in gaps of knowledge is the opposite of “reason”. That’s why becoming an atheist is so liberating. You’re no longer restricted to inventing supernatural reasons to explain things that you don’t understand. That’s pretty much what religion has always been. A creation of man to explain things that he didn’t understand, and fill in the gaps of scientific ignorance with superstition and tradition. Science requires no faith, and no beliefs. It only requires ideas that can be tested! Experiments and observations. Hypotheses, theories, and laws that explain facts and observable phenomenon. The concept of a god (or any supernatural phenomenon) is neither testable or falsifiable, nor are they objectively observed, which thereby makes them inherently unscientific. Faith in something that cannot be demonstrated to exist is not “reasonable”, it’s religion!