During the past 30 years I've been in the nasty epicenter of many controversies and credit disputes, either as a defender, apologist, or clarifying agent--all ostensibly done on behalf of others.
One of the things I learned, mostly the hard way, is that complete originality (in magic) is rare. Also, almost every idea, innovation, variation, and improvement is in someway ancestrally tied to other, previously published material. We are indeed "parasites of our precursors." It's merely a matter of degree.
What further clouds the matter is the phenomenon of legitimate reinvention. This likewise happens all the time.
Anyone who has deeply studied the curious and fitful history of tricks, sleights, and subtleties, tracking them back to their lairs, discovers the amazing links, strong influences, points of inspiration, and direct derivations that exist. It's truly mind-boggling. And it generally results in what I call "combinatorial creativity." It is and has been rampant in magicdom for a long, long time.
Even when you closely examine the work (in detail) of our supposedly "original" thinkers, after all the dots are connected, their material is less original than assumed.
Even the work of our revered teachers, Marlo and Vernon, reveal surprising and unexpected "connections" to past works. This kind of phenomena smacks of what gossipists are wont to call "theft" and shameless "borrowing." So it goes...
...We should nevertheless be intrigued by all "ancestral ties" and we should then try to more precisely figure out what all our influential, glorious "parasites" bring to the table. Where would we be without them?
Side-bar: When Frank Garcia initially published MILLION DOLLAR CARD SECRETS, I PRIVATELY sent him a long list of omitted credits. These, as many of you know, were ultimately included (without credit to me) in Frank's second (green) book. In the meantime, Frank was very displeased with me for pointing out all the missing credits.
Regardless, all my vis-a-vis sessions with Frank were always interesting, stimulating, and cordial. Don't get me wrong. We still disagreed about many, many things and I never gave him a "pass" regarding the subject of those "credits."
I feel the same way regarding other "borrowers" who fail to honor their precursors.
Although I don't fancy myself to be a historian or high-ranking member of the Credit Police, I am, despite what my detractors contend, interested in revealing the evolution of ideas. I'm equally intrigued by the process wherein and whereby our creative gentry quarrel, cooperate, and (most of all) collaborate in acknowledged and unacknowledged ways.
One could do worse...and I often do.