D.T., I see your point, however method AFFECTS effect. If someone were to invent a trick where a die is rolled, numbers added, a card counted down to, remembered, and the magician names the card; we would say the effect is one of mind reading. Is this the same "effect" as telling someone to think of any card in a pack, and then naming the card.
Well, yes and no.
So, effect is a very big word which I think may often be innacurate due to its largeness. In fact, I have written and spoken about a new way to break apart magic which eliminated these fuzzy lines. It is, however, long and fairly tedious so I don;t know if anyone would be interested.
But, back to the original question, but backwards.
If the effect is the thing, then if I were to come up with a revolutionary new way to perform, say, the linking rings, would I have no real right to it as my intellectual property? The effect is ancient. So, is my method open to be taken by any and all? Well, what if someone looks at my handling and they are "more, better fooled" by it, than the classic method. Is the "effect" the same, though in both cases rings are linking?
What if I come up with a new framing for the effect which "puts it in a new light?" For example, Snowstorm is old, but Peter Samelson's thinking made it something it never was before (at least as far as I was aware). It MOVED audiences. But the EFFECT isn't Peter's, or is it?
Sure the "trick" isn't Peter's, but the effect/impact it has on the audience maybe is, this impact produced as a combination of elements.
So, maybe we should break apart the concepts of "trick" i.e. phenomenological happening; "effect" which is that which is perceived to have happened and the manner in which it seems to have happened, and "aesthetics" which is what we feel about what has apparently seemed to have happened. So we have domains for method, presentation, and art. Though seperate, they are all of course interconnected.
(Ok, thats the very basis of my system, which I didn't mean to go into. But regardless of what you think about the break down, I think the exploration of method/effect/impact and its relationship to IP is worthy of consideration.