Originally Posted by
Scott R. Brown
In essence he is correct. However, he is correct according to a specific context which is different than the context that was implied in the question. In a sense he is saying, "Yin is Yang and Yang is Yin, it is the interplay of the two principles that causes life." Which principle "appears" to predominate at any one time depends upon the context one is using to define a specific phenomena.
I use the example of three bowls of water to illustrate this principle.
Let us take three bowls of water. One has 40*F water, the second has 60*F water, and the third has 80*F water. The question is, is the second bowl filled with warm or cool water? The answer depends upon which other bowl we are contrasting it with. When contrasting it with 40* water it is warm, when contrasting it with 80* water it is cool. Inherently it is neither warm nor cold. It is one or the other depending upon the context; depending upon what it is contrasted with. Inherently a block or movement or limb or mind is neither alive nor dead, we merely "refer" to it as live or dead to illustrate contrasting phenomena or conditions of being. The terms are useful expedients that allow us to communicate apparent differences between phenomena.
Since an arm is living flesh your Sifu is correct, it cannot be anything other than alive, however according to the context of the principles under discussion it may be "referred to" as live or dead.