Advanced waves come at us from the future, retarded waves smack us from the past. Where they meet is the present, where we live. But we're not alone, of course, and what other people/things/planets do has an impact on what happens to us. What if, when something of magnitude happens on another timeline, we ride an advanced/retarded set of ripples which have created a standing wave? It only would be there for a moment, as we are constantly travelling through time, but at times of choppiness, with lots of events happening round our timeline to potentially affect us like rainfall on a pond, there would be lots of these standing waves cropping up at once. Once in a while, some big fish might jump in the pond to smack us across the face with its tail, and we get a big significance which somehow we recognise as being big, even though we've no idea why it happened.
Two events colliding in our own timeline, pushed together by the impact of the standing-wave effect, would make past and future merge into two events which are intrinsically instantly connected, simply because it has to be that way - the past and future are crossing at a standing point, balanced for a moment without movement. The important thing from our point of view, if this scenario is correct, is that when we get smacked with a major synchronicity something big has flopped into our ocean and we are likely to get something from it at some point in time. Like a radar beacon flashing across our world line, synchronicity is there to prove that everything is truly, genuinely, intimately connected and we have every right to trust that there's a bigger picture, and some kind of plan - whether or not there's anyone to master it being irrelevant, the significance being only that a master plan there is. Ballerina's skirt, eh? With some guy looking up it, I guess.
What is loveable about all this stuff is that it might actually be true. If it is, then there's no fluffy-bunny cosiness about a belief system that's constantly open to re-interpretation. There's absolutely no constant to worry about because the universe just doesn't work like that. What's the point of laying constants in the face of uncertainty?
The Uncertainty Principle'll just tread all over them and do exactly what it wants, which won't ever be the same as what it did before.
Sixpence None the Richer