The core of the lean startup is the application of the scientific method to systematically and consistently gain knowledge about product/market fit. The scientific method is the only reliable way for gaining knowledge about the natural world that has been discovered in all of history. Only a kook would argue against it. Luckily that's not what Marc Andreessen argues.

Marc seems to believe that the Lean Startup approach is not applicable to "audacious" ideas, citing the Macintosh. This is, of course, not the case. The scale of a project might make experimentation more costly, or more difficult, but it still occurs. For example, the Macintosh was preceded by the Lisa. Apple learned from the Lisa (too complex, too slow) and hence the Mac was simpler. Sometimes experimentation occurs not at a company level but at an industry level. To use Apple again, the early experiments leading up the iPhone were performed by Apple (Newton, iTunes Phone), Palm, and RIM. It's not like the iPhone sprung fully formed into an empty market, much as Apple would like you to believe this.