You could try reading the YC article, which says, "I’ve been intrigued by the idea for a while, and although there’s been a lot of discussion, there’s fairly little data about how it would work."

It's clearly an experiment to get real data about basic income, which has not been done before. Even if basic income is not viable, having data will be useful.

Two things:

1) I did not qualify the viability of basic income in my statement. I just gave my opinion on what the author might say on this issue given that he is highly critical of the financial viability of the US social system. (he wants to reduce spending)

2) YCombinator doing a test doesn't mean that it is a viable model.