Edison and philosophical progress

I stumbled across the following quotation from Thomas Edison, and thought it might offer a way to give a positive answer to the question (which is the subject of an upcoming conference) "Does philosophy make progress?"

If I find 10,000 ways something won't work, I haven't failed.

I think there are several areas in philosophy where people show fairly conclusively (modulo choice of logic) that a certain set of prima facie plausible views are inconsistent and/or have counterexamples. So we have eliminated certain possibilities (least as well as any intellectual endeavor can eliminate any possibilities), and that elimination constitutes progress.