2. Our idea of "everything the body needs" can change.
3. We don't know the long term effects of relying solely on it.
The author spends a lot of time on stupid counterarguments. Seriously, do your homework.
I still wouldn't want to be the guinea pig to exclusively live off of Soylent.
2+3. Having said that, there is plenty of research on "Total Parenteral Nutrition" and "Enteral Nutrition" for those that cannot consume regular foods for medical reasons. It isn't exactly a solved problem however, there are still issues.
"More than 25,000 phytonutrients are found in plant foods. WebMD takes a look at these six important phytonutrients -- and their potential health effects: Carotenoids, Ellagic acid, Flavonoids, Resveratrolm Glucosinolates, Phytoestrogens"
Find them in Soylent? It's cute that you put nonessential nutrients in quotes though. It's like this foreign term that only I use.