The example is often quoted of a tree falling in a forest, and whether if no-one observed it, it really happened. This is usually part of a philosophical debate, looking for a theory of reality, of how things are, but it just-misses an important gateway to insight.
The point of the example is that the event is not KNOWN by anyone, so whether or not it happened lacks any experiential evidence. If, instead of asking about “reality” we ask about appearance, it is clear that there was no appearance of a tree falling – because no-one saw it. All appearance – all awareness – involves an aspect of being known, and an aspect of what is known.
When we see something (or perceive with any other sense) there is awareness which involves these two aspects, and although these aspects are utterly inseparable in any appearance, we interpret the situation as being a person, me, knowing a separate thing.
even my body
We draw an imaginary line around our body, classing anything outside that as not me. Curiously we do this even when the object we perceive is one we class as also being me – eg my knee. Somehow we ‘contract’ the me-boundary to allow a knowing-me to perceive a known-me. In fact we cannot find any part of me which cannot be treated as an object in this way, that is, we cannot find any Knower as an object – after all, what could possible know it?
So we have no evidence, no experience, that such a Knower exists, separately from the object known. We continue to split any instance of awareness, any appearance, into Knower (knowing-consciousness) and known-object, even though there could be no awareness without both these aspects and there is no evidence of this split.
what about thinking?
To take this intellectual realisation and notice it in our experience – that is, to cease to interpret our experience in the complicating way we’re used to, requires close observation of the kind possible in meditation. Even when the appearance we consider is that of thinking, we assume there is a separate thinker. How could that work!
Observing thinking should reveal to us that this way of describing it is a case of ‘this mountain and that mountain’ – where ‘this’ and ‘that’ vary according to which one you are observing from. There was just thinking, and then the interpretation is made (another thought) that you are now the one who observed it. You “thought” yourself separate from that first thinking. It’s a trick you fool yourself with, a “sleight of mind”.