Of infinity in any of its aspects we can really know nothing, but that it exists and is inconceivable. It is a thought that oppresses and overwhelms. Yet many speak of it glibly as if they knew what it contains, and even use that assumed knowledge as an argument against views that are unacceptable to themselves. To me its existence is absolute but unthinkable—that way madness lies.
Alfred Russel Wallace, Man’s Place in the Universe
I love this book. I can think of few better introductions to cosmology or a discussion of the religion/science issue. Make sure you get one of the editions with the final chapter in, like mine.