I was reading "In Search of Alpha" (NewScientist September 9-15, 2006). In the article they are trying to calculate and measure alpha (but this in not relevant to my topic). In order to calculate alpha one has to sum the probabilities of all possible interactions between sub-atomic during an interaction (collision of particles). While it seems manageable for a small number of quantum particles, there's a problem. One has to account for the 'quantum foam' which may spontaneously create (and normally destroy immediately) additional particles. By chance, these temporary particles may interact with the ones of interest.

Seemingly since these particles must quickly disappear back to the nothingness, no harm done. However, this is a real effect. The experimental part of the article indicates that particle accelerators recognize certain particle interactions by the pattern of by products. These spontaneous particles actually affect a percentage of interactions in significant enough way to complicate pattern recognition in particle detectors of particle accelerators.

If you didn't follow all that, don't worry about it. The thing that struck me is that these temporary quantum particles are generally referred to as spontaneous and random. I think this means the normal chain of cause and effect is not followed. Energy debt quickly corrects the situation and destroys the particles. Although they shortly disappear, it would seem that their effects don't. So this would seem to indicate that effects without causes happen all the time.

On a macro level this would seem to be equivalent to the thought experiment of an inventor of time travel. In this scenario, the inventor's future self builds a time machine and goes back in time to tell himself how to invent time travel. The question is where did the idea for time travel actually come from.

Thoughts, clarifications...