人是先有欲望，还是先有愉悦？

人们普遍想过先有鸡还是先有蛋的问题. 类似的但是更加困难的一个问题是：人是先有欲望，还是先有愉悦？—- 究竟是人要做某件事的欲望产生了愉悦的感觉？还是因为想获得愉悦感这个动机驱动了人们做某件事的欲望？

这个问题好像很不好回答，因为有多种可能性. 下面是一些相关例子.

人可能是想获得“甜”这种愉悦感从而有了“拿一块糖并放入嘴里”这个冲动.

而对喜欢攀岩的人来说，因为攀岩的后果并不肯定总是愉悦的，比如攀岩者可能出事故从悬崖上摔下. 那么他的成功愉悦只能是“要攀岩“这个行动欲望中多种可能结果的一种. 除了自杀者，没有人希望由丧失性命这个结果来驱动“去攀岩“这个欲望. 这个例子似乎在说 “要攀岩“这个欲望并不绝对依附于愉悦这个结果. 

更复杂的一个例子是做慈善事业. 一个人去做慈善是由于追求做了善事之后的心理满足亦或是追求现实中的名利收获（如果是这样，这位行善者一定会寻求行善回报)? 还是行善本身就是“欲望“，或者称为动机，不追求行善这个行为能给行善者本人带来的任何精神或者物质上的“愉悦”？ 多想想这个问题，或许能给困挠一些国人的父母/子女关系问题带来一些启示. 

17世纪的英国哲学家洛克John Locke在这方面也做了不少探讨与论述. 洛克在这个问题上似乎也无法做到逻辑自洽. 下面就是罗素在引述洛克关于欲望与愉悦的思考并加以评论的文字. 在这段话的最后，罗素总结出哲学家包括洛克在提出命题后，在论证过程中为什么会出错的原因. 而这个出错原因在今天的现实世界中，很容易在国内各类专家的言行中暴露出来. 用错误的方法是无法对一个目标系统做出正确的验证，无论是证实还是证伪. 

下面这段文字很晦涩难懂，但包含了很丰富的内容.  我读西方哲学的一个体会是，不管多难多“无用“的问题，他们都有人去做系统性的逻辑思考. 这些哲学家有时也在学说（doctrine）的正确性，精确性与逻辑自洽中挣扎，在两者中作出他们自己都不情愿的各种各样的思想妥协. 尽管这样，他们还是一代又一代的不停地在人类认知论上做出各种探索，产生出丰富多彩的哲学思想，指引着社会前进. 

In the first place, to say that men only desire pleasure is to put the cart before the horse. Whatever I may happen to desire, I shall feel pleasure in obtaining it; but as a rule the pleasure is due to the desire, not the desire to the pleasure. It is possible, as happens with masochists, to desire pain; in that case, there is still pleasure in the gratification of the desire, but it is mixed with its opposite. Even in Locke's own doctrine, it is not pleasure as such that is desired, since a proximate pleasure is more desired than a remote one. If morality is to be deduced from the psychology of desire, as Locke and his disciples attempt to do, there can be no reason for deprecating the discounting of distant pleasures, or for urging prudence as a moral duty. His argument, in a nutshell, is: "We only desire pleasure. But, in fact, many men desire, not pleasure as such, but proximate pleasure. This contradicts our doctrine that they desire pleasure as such, and is therefore wicked." Almost all philosophers, in their ethical systems, first lay down a false doctrine, and then argue that wickedness consists in acting in a manner that proves it false, which would be impossible if the doctrine were true. Of this pattern Locke affords an example.