Ex Machina, a Gallegher novelette by Henry Kuttner as by Lewis Padgett.
Galloway Gallegher is one of the world’s great inventors – but only when drunk. Once he sobers up, he is considerably duller and unable to remember the specifics of his previous problem-solving – focused, in this instance, on a contract for a company that sponsors hunting trips. The problem is that in the course of fixing this problem on the night before the story opens, Gallegher somehow vanished both his grandfather and the hunting company’s representative, and wakes up the next morning with a mysterious rock-like “dynamo” in his workshop, and some sort of small, brownish creature that moves too fast for the eye to see and drinks all of his liquor before he has a chance to enjoy it himself – leaving him to solve this problem while sober, you see. This unlikely setup (apparently one in a series of shorts about the character) is abetted by a series of similarly unlikely contrivances (ie a camera covered up at an inopportune moment, a robot shut down for being too sassy, etc). Said robot peppers the text with philosophical ruminations on epistemology and the nature of the human mind, and also proves to have had the answer to the mystery all along – Gallegher just never asked the right questions.