This quote is rather unclear - I had to look at the original source to determine what it might mean - and equally importantly, it seems rather useless. Schaffer wants to establish ... something about being real, i guess, by his philosophy, but I don't see how he would expect anything different thereby.
There is some tendency - or bias, if you wish - on this site to take reductionism for granted. Schaffer might help here. By reading him we might come to expect, with some probability, scientific findings that point to an infinite descent of ontological levels, and so to the failure of reductionism. His other goal is to argue against a stronger form of reductionism that comes easily with the first: eliminativism in regard to, say, qualia, or beliefs.
(Last month's started a little late, I thought I'd bring it back to its original schedule.)
A monthly thread for posting any interesting rationality-related quotes you've seen recently on the Internet, or had stored in your quotesfile for ages.