Mere Christianity, in The Complete C. S. Lewis Signature Classics

p. 31

“It is no good asking for a simple religion.  After all, real things are not simple.  They look simple, but they are not.  The table I am sitting at looks simple: but ask a scientist to tell you what it is really made of—all about the atoms and how the light waves rebound from them and hit my eye and what they do to the optic nerve and what it does to my brain—and, of course, what we call ‘seeing a table’ lands you in mysteries and complications which you can hardly get to the end of.  A child saying a child’s prayer looks simple.  And if you are content to stop there, well and good.  But if you are not—and the modern world usually is not—if you want to go on and ask what is really happening—then you must be prepared for something difficult.”

p. 31

“Besides being complicated, reality in my experience, is usually odd.  It is not neat, not obvious, not what you would expect.  For example, when you have grasped that the earth and the other planets all go round the sun, you would naturally expect that all the planets were made to match—all at equal distances from each other, say, or distances that regularly increased, or all the same size, or else getting bigger or smaller as you go farther from the sun.  In fact, you find no rhyme or reason (that we can see) about either the sizes or the distances; and some of them have one moon, one has four, one has two, some have none, and one has a ring.  Reality, in fact, is usually something you could not have guessed.  That is one of the reasons I believe Christianity.  It is a religion you could not have guessed.  If it offered just the kind of universe we had always expected, I should feel we were making it up.  But, in fact, it is not the sort of thing anyone would have made up.  It has just that queer twist about it that real things have.”