I'm going to be appearing this weekend on the strangely addictive show bloggingheads.tv. If you're not familiar with it, it's a show composed of two talking heads staring out of your screen at you, holding forth for an hour on whatever topic they choose (politics, television, science...). Actually, each speaker is staring into a computer camera and talking on the phone to his or her partner in chat. On Saturdays, two of our most provocative science writers, John Horgan and George Johnson, take to the tubes. Horgan asked me to join him this week. I've known Horgan for several geological eras, ever since I was a young fact-checker at Discover, trying to make heads or tails of a story Horgan wrote about how universes can bud off baby universes. He has always had a fondness for the far reaches of science, which led him to write his first book, The End of Science. I found a lot to ponder in the book, but I didn't buy his central argument--that all the great scientific discoveries are behind us. (For the details, see this review of another book I wrote for the journal Nature.) That certainly seems like a good place to start our discussion, and we've got plenty of other ideas as well. We're actually recording the piece midday Friday (EST), so if you want to make any requests, we can do our best to bloviate about them.