橙子兼有用来吃和打人的功能─对於饥饿的人，领悟到的只是吃的功用；对使用的於愤怒的人，所想必然是用以击中对方的鼻子。环境(物质或生物)对其中的生物所提供的可能性─affordance既不客观也不主观─你领悟到，这些可能性存在；领悟不到，可能性依然存在。至於对这种提供，是理解成暗示还是明示，我倒认为无关紧要。

affordance既不客观，也不主观

领悟不到，可能性依然存在

正是。如果椅子被理解为'升起的工作台'，它就不一定是四条腿撑着的四方面，它可以是由任何材料举起的随意曲线的面。如果椅子被理解为'藏猫猫的地方‘，椅子面下面我们平常看不见的地方的设计就很重要了。如果椅子被理解为'武器’，椅子可能就根本不需要一个面了。

The fact that a stone is a missile does not imply that it cannot be other things as well. It can be a paperweight, a bookend, a hammer, or a pendulum bob.It can be piled on another rock to make a cairn or a stone wall. These affordances are all consistent with one another. The differences betweeen them are not clear-cut, and the arbitrary names by which they are called do not count for perception. If you know what can be done with a graspable detached object, what is can be used for, you can call it whatever you please.

The theory of affordances rescues us from the philosophical muddle of assuming fixed classes of objects, each defined by its common features and then given a name. As Ludwing Wittgenstein knew, you cannot specify the necessary and sufficient features of the class of things to which a name is given. They have only a 'family resemblance.' But this does not mean you can not learn how to use things and preceive their uses. You do dont have to classify and lable things in order to percieve what they afford.(1986:134)