Consciousness -- as in the sheer fact of experience -- is itself the base "reality," out of which everything is made. If you examine everything you're calling "the universe," all you will ever discover is sights, sounds, thoughts about sights and sounds, belief (or certainty) that those sights and sounds are caused by something external, etc. What are all of those made of? Consciousness, of course.
In this reality, "brains" are the entities that consciousness has dreamed up to demonstrate correlations with conscious properties. In our reality, we therefore say that "the brain causes consciousness."
If you investigate your experience closely, you'll discover that the epiphanies "I exist," "I am conscious," "I am alive", "a world exists" all point to the same ineffable "miracle" of existence, the one "substance" of which all realities are made.
Upon hearing this, perhaps the mind thinks "just as there are realities that exist without time and space, why can't there be some without consciousness?" There's a very interesting answer to that question, but it won't come in the form of thoughts.
Of course, there's no reason to believe any of that. On the other hand, as the Buddha said, don't believe me....
There is not even a reason to believe that the "outer universe" has such things as space and time or information as we know it, and no way to know what a "computation" might comprise in such a situation.
Maybe the situation is not that pessimal, and an outer universe is much like ours, but to prefer that believe one would need evidence, of which we have none.