Full Idea
We cannot transform a non-black non-raven into a raven to see whether we get a simultaneous transformation from non-black to black, in the way we can transform a flame without sodium into a flame with sodium.
Clarification
Sodium flames burn yellow
Gist of Idea
We can't turn non-black non-ravens into ravens, to test the theory
Source
Peter Lipton (Inference to the Best Explanation (2nd) [2004], 06 'Unsuitable')
Book Reference
Lipton,Peter: 'Inference to the Best Explanation (2nd ed)' [Routledge 2004], p.98
A Reaction
A white shoe would be an example of a non-black non-raven. People mesmerised by the raven paradox are too concerned with investigation being a 'logical' process. Lipton makes a nice point. We need to know the nature of ravens.