Say's law
The first criticism is that, following Say's law and the related circle of ideas, if demand slackens, prices will fall (barring government intervention), and the resulting lower price will stimulate demand (though at lower profit or cost – possibly even lower wages). This criticism in turn has been questioned by New Keynesian economists, who reject Say's law and instead point to evidence of sticky prices as a reason why prices do not fall in recession; this remains a debated point.