Rob Arnott challenges the growth versus value framework as too simplistic for today's markets. He argues that what's cheap can be value, regardless of growth, and vice versa. Arnott advocates for fundamental indexing, which weights companies by business size, not market cap. He also warns against the dangers of momentum chasing and narrative-driven investing in mega-caps like Palantir (PLTR), and emphasizes the importance of anchoring on fundamentals and using common sense when evaluating investment opportunities.