I'd do it myself, but I'm busy.

"Such a thing is impossible," declared Dr. Ransome emphatically, in the course of the conversation.
"Nothing is impossible," declared The Thinking Machine with equal emphasis. He always spoke petulantly. "The mind is master of all things. When science fully recognizes that fact a great advance will have been made."
"How about the airship?" asked Dr. Ransome.
"That's not impossible at all," asserted The Thinking Machine. "It will be invented some time. I'd do it myself, but I'm busy."

Jacques Futrelle, The Problem of Cell 13.