the hole in a theory

The effect of the observer on the observed. If a tree falls an a forest and nobody hears it, does it make a sound? The answer depends on our definition of sound. The falling tree always produces vibrations in the air. Also the observer's thinking changes what is "sound", but doesn't change the nature of the event. If we define this as sound, the answer is yes. If we define sound as something that must be heard, the answer is on. So the presence or absence of an observer makes the difference with this definition.