Researchers now postulate that addiction requires two things .
研究者假定成瘾需要两个基本条件。
It seems that they would look for any explanation rather than postulate a new particle .
他们似乎更愿意寻找任何可能的解释也不愿去假定存在这种新粒子。
First , we must postulate that if souls exist , they must have some mass .
第一，我们必须假定灵魂存在，他们必须保有物质。
But the postulate worked only as long as it was applied to the exchange of physical goods .
但是这个假定只在应用于实物交换时才成立。
I think we can postulate a utility function along the following lines : having a christmas tree up during the christmas season brings positive utility , but diminishing marginal utility over time .
