In my last post, I finished up like this: "Magic, in the sense that I want to talk about it means the art of understanding and manipulating the relationship between perception and reality."
There's a sentence that needs unpacking, if ever I saw one. I'll start with the second half first - the relationship between perception and reality.
It's not too hard to accept, if you look at it rationally, that there's a gulf between objective reality* and our perception of it. Starting at the most basic level, our senses are attuned to a very specific (and, cosmically speaking, quite small) spectrum of data: we can only hear at best between 20 Hz and 20,000 Hz** (and this degrades as we age); we can see only a small range of the available radiation spectrum (visible light) and feel only a tiny range outside that (heat); our chemical sensitivity (taste and smell) is negligible compared to many other species; and because we lack whiskers or electrical sensing mechanisms, our sense of touch pretty much ends at our skins.
On top of this, our brains only have a limited "pool" of processing power to apply to the task of processing and sorting the sensory information that's available - and it's the same pool of processing power it uses for thinking and telling the body to execute voluntary movements. To save time and power, we have a bunch of cognitive shortcuts or "filters" in place to fit incoming data to pre-determined patterns and interpret it in light of pre-determined principles.
For example, if you look at this:
This is a mostly-good-enough solution. It does save time and energy and vastly improve our survival rates*** but that doesn't really change the fact that most of what you see when you look at the picture above is not the chair-that-you-see, but rather your ideas-about-chairs made manifest.
Most people probably don't feel especially strongly about chairs, but if you did, you can see how easy it would be for your ideas-about-chairs to be strongly coloured by that depth of feeling. in fact (because ideas are sticky, and tend to cohere to one another in strange ways) chairs might become a symbol for you of all of those strong feelings.
Magic operates in this space of "ideas-about-things" and the feelings and sub-concepts that attach to those ideas.
*Assuming there is such a thing - but that's an argument for another time...
** This is less than it sounds like, because an octave is double the original frequency - so from concert A to the next one is a gap of 440 Hz, while the gap to the next A up the scale is 880 and the one after that is 1760 (and so on and so forth).
*** You don't need to stop and think to decide that stepping out of the way of a bus is a good idea, for example.