"No substantive criticism" seems to be filling the same role as "ridiculous". Applying DCF doesn't seem ridiculous, but there is still an argument to be made a

"No substantive criticism" seems to be filling the same role as "ridiculous". Applying DCF doesn't seem ridiculous, but there is still an argument to be made about whether humans that exist now are each more important to our current plans than humans that (may) exist in two hundred, two thousand, or two million years.