I've worked with a bunch of people who don't have degrees. At the more junior level, you can tell the difference, because while they tend to be really smart and can pick things up quickly, they have funny holes in their knowledge -- CS theory that you'd only pick up from a CS textbook, stuff like Big O notation or A* search (ok maybe that one is a bit more common now, but in the early 00s you didn't really learn that without a textbook).
By the senior levels you can't really tell the difference between someone with or without a CS degree. Experience definitely beats textbook knowledge after a couple of years.
By the senior levels you can't really tell the difference between someone with or without a CS degree. Experience definitely beats textbook knowledge after a couple of years.