Marc Andreessen is casting anyone against "techno-optimism" as an enemy.Justin Sullivan/Getty ImagesBillionaire VC Marc Andreessen wrote a manifesto plugging "techno-optimism. : Andreessen, the eponymous cofounder of Silicon Valley investment firm Andreessen Horowitz, is known for firing off lengthy memos in defense of technology, the sector that has enriched him. His latest is a 5,000-word manifesto about past, present, and future civilization being built on innovation. "We believe in the romance of technology, of industry," he writes, via digressions on the artist Andy Warhol, economist Milton Friedman, and the myth of Prometheus.