Actually it's classical economics. Say's Law. Keynsian economics turned the idea on its head and most economists don't buy it today,but it was the dominant idea behind economic policy for a couple of centuries.

No one knew they needed a VCR before Sony released the Betamax. No one knew they needed a smartphone until Apple released the iPhone. Supply can create demand. It doesn't always work,which is why during the Depression Keynsianism was adopted because it was felt that classical economics had failed. The stagflation of the late 1970s was considered impossible under Keynsian theory and that led to a resurgence of supply side - or classical - economic policy.

Economies are complex systems and no one really knows how they function under all circumstances.

I have a huge supply of typewriters. Can't seem to find the demand.

Wow! Someone defended Rick Perry's logic. Amazing. The demand for stoopid is apparently growing because Rick has an unlimited supply.

Where exactly did I defend it? I just suggested that he was citing, albeit poorly, economic theory that was dominant until the last 90 years or so. Keynesian theory may be dominant now, but lots of economists still disagree with it. Here's a little better explanation.

On another note, calling someone stupid for offering an explanation is why we can't talk any more.