'The yellow killer... disrupts the colour vision of anyone who sets eyes on it; and it disrupts all other brain processes as well, thereby causing instant death... Its special shade of yellow - "killer yellow", is fatal regardless of what the coloured thing may be. This colour does not typically cause colour experience. It never does, and never could so long as we retain our vulnerability to it.'
- David Lewis, in 'Naming the Colours', with the following footnote: 'The example of killer yellow is due to Saul Kripke, in lectures many years ago. I am obliged to note that what I say here may not correspond to the whole of what Kripke said in those lectures.'