Take a look at Milton Friedman's thoughts as well. I believe MLK's stance was largely influenced from what he knew about Negative Income Tax. https://www.youtube.com/watch?v=xtpgkX588nM
I'm surprised I don't see negative income tax brought up in more basic income discussions. A NIT with a flat tax[1] has always seemed to me to be a really pragmatic way to implement a basic income.
A negative income tax has the same issues as a basic income. It isn't remotely affordable based on the current tax rates without large cuts to social spending and/or eliminating it entirely.
[1] https://en.wikipedia.org/wiki/Negative_income_tax#Flat_tax_w...