法国商人J B Say曾设想过，供给可以创造自己的需求（布劳格，1997）。他说，如果商品是在市场上生产和供应的，市场就会通过对这些商品的需求来自动消除。这项法律是在十九世纪颁布的，凯因斯和他的追随者已经证明这是多余的。这在宏观经济意义上可能是正确的，但在微观经济层面上不能完全抛弃。然而，在现代背景下，供给不能创造需求。由于市场上有如此多的同类产品，单纯依靠供应不会产生理想的结果。然而，供应之前或之前的APT营销策略肯定有帮助。现代说的法律已经成为“营销（而不是供给）创造需求”。
The French businessman J B Say had postulated that supply can create its own demand (Blaug, 1997). He said that if goods are produced and supplied in a market, the market would automatically clear it up by creating demand for those goods. This law was given in the nineteenth century and has been proved redundant by Keynes and his followers. While this may be true in the macroeconomic sense, it cannot be discarded completely in the microeconomic sense. In the modern day context, supply alone however cannot be liable for creating demand. Since there are so many similar products in the market now that relying alone on supply will not yield the desirable result. However, supply preceded or preceded by apt marketing strategy definitely helps. The modern day Say’s law hence has become “marketing (not supply) creates demand”.
McKenna (1991) writes that in the modern day, “marketing is everything and everything is marketing”. It is the new way of doing business which makes you own the business and not just do it. Thus marketing is the new way of creating demand. It is a more advanced form of advertising which creates a dialogue between the company and the customer to make the former understand what the customer really wants thereby fulfilling their needs.
It is important here to distinguish between marketing and advertising. Advertising is the old way of marketing wherein the producers create a monologue between the buyer and the seller to showcase the features of the product. Marketing on the other hand is the trick to make customers realize that they really need the product. Marketing is the way of demand creation (Slywotzky, 2011) whereas advertisement is now merely the means to fulfil the existing demand (Fou, 2009).