西方经济学从没有说过供求决定价格-经管之家官网！

先复制两段话：
百度百科
“供求关系（supply-demand relationship）
　　供求关系指在商品经济条件下，商品供给和需求之间的相互联系、相互制约的关系，它是生产和消费之间的关系在市场上的反映。
　　在竞争和生产无ZF状态占统治地位的私有制商品经济中，价值规律通过价格与价值的偏离自发地调节供求关系，供大于求，价格就下落;求大于供，价格就上升。 ”
再看wikipedia
“Supply and demand is an economic model of price determination in a market. It concludes that in a competitive market, the unit price for a particular good will vary until it settles at a point where the quantity demanded by consumers (at current price) will equal the quantity supplied by producers (at current price), resulting in an economic equilibrium of price and quantity.

The four basic laws of supply and demand are:[1]

• If demand increases and supply remains unchanged, then it leads to higher equilibrium price and higher quantity.
• If demand decreases and supply remains unchanged, then it leads to lower equilibrium price and lower quantity.
• If supply increases and demand remains unchanged, then it leads to lower equilibrium price and higher quantity.
• If supply decreases and demand remains unchanged, then it leads to higher equilibrium price and lower quantity.”
  

各位看清楚了吗？任何科学的理论都是有假设前提的，西方经济学中的供求关系讲的是在“商品经济条件下，在竞争和生产无ZF状态占统治地位的私有制商品经济中，in a competitive market”的情况。稍微受过现代科学训练的人都不会不加任何前提假设就绝对支持或反对“供求决定价格”。很多同志总喜欢先歪曲别人的理论，再去批判自己歪曲的理论。他们先故意忽略别人的前提假设，再提出几个反例，最后宣布此理论不成立。很惯用的伎俩啦。