Experiment · Philosophy of language · Perception

Duck or rabbit?

Wittgenstein used this old drawing to ask what changes when a picture "flips". The lines stay the same, and yet you see something else. Here the picture drifts slowly from duck to rabbit and back. Tell it when it flips for you.

Two slow sweeps

First the duck becomes a rabbit, then the rabbit becomes a duck. Press the button (or the space bar) the moment you see the other animal.

Don't try to be clever. Just say when you see it.

I contemplate a face, and then suddenly notice its likeness to another. I see that it has not changed; and yet I see it differently. I call this experience "noticing an aspect".Wittgenstein, Philosophical Investigations, Part II, xi