when we move our hands or our fingers it appears to us as though it is our hands and our fingers that are doing what they want to do. but it is our muscles and our tendons that act as the "strings" which are making our hands and our fingers move and when the pull of the flexion strings is complete it is the opposing extensor strings that will bring the wrist and fingers back to their original position.

but it is we who are the controllers of those strings when we have the idea to move our hands. we are the puppeteers of and in our own body which makes it move. however it is the chemicals, specifically the sodium and potassium ions, and electrical action potentials that control our ideas to move our bodies. so in fact we are the puppets and the chemicals are the puppeteers which allow us to have the ideas to cause our body to move.