That's what he says in his column today. This seems more than a bit fantastic given the run-up in prices to $150 a barrel in 2008 followed by a plunge to less than $40. Most of these movements might be attributable to growth and then recession in the real economy, but it would require a story of incredibly inelastic supply and demand to fully explain these movements by the fundamentals of the market. There is research (here [link corrected] and here) that shows the opposite of Samuelson's assertion.