In his book Hyperspace, Michio Kaku devotes just over a page to discussion of the notion of the Collapse of Causality, a Disaster that is a likely consequence of the spread and proliferation of time travel technology. If you think Temporal Paradox is bad, just imagine what would happen if time travel ever became so accessible that kids took the family Time Machine out for a ride. If the sort of irresponsibility we show in private life were coupled with the power to alter the past, the earth would quickly be unlivable. Think of all the things you'd change if you could, and then stop and consider for a moments the billions of other people and all the things they'd change if they could.
Collapse of Causality is Temporal Paradox to the Nth degree. A continual miasma of competing timelines and rewritten history that dissolves all cultures and all certainty. This threat of mass alteration of the past has such far-reaching and has consequences that would be impossible to control. Billions of people are being unborn and unkilled every second, and history is twisting all around us. It may manifest overtly, with things actually changing before your eyes. Or, it may just be a force that drives mankind collectively insane. You can no longer trust anyone or anything. Life becomes utterly unpredictable, an anachronistic wash of random unrelated developments. Things and people appear, change, and vanish, for reasons unexplained.
Even if we genuinely tried to control ourselves, the fact remains that even the slightest screw-up would muddle up everything. Entire trilogies of movies have been made, based around the screw ups of a single Bewildered Time Novice. Given how much chaos those tails involve, it's hard to imagine what thousands, or billions of such people would do to history. And lets face it, in this society where Space Tourism is the hot new business, can we really doubt that Time Tourism would catch on? All our most important events of history would be swarming with extras and lookey-loos from the future. Stephen Hawking has used the absence of such Time Tourists as evidence to support his conjecture that time travel is actually impossible. We should be thankful for that, because even if you're charging millions per trip, and strictly controlling the tourists actions, you can't rule out disaster, as Ray Bradbury's Sound Of Thunder illustrated.
This is all that stands between you and total collapse of causality:
- Chronology Protection Conjecture - as Hawking says, Time Travel may be impossible.
- Clock Roaches
- Delayed Ripple Effect - it may be the changes just haven't reached us yet
- Novikov Self-Consistency Principle
- Ontological Inertia
- Time Police
- You Can't Fight Fate
Game and Story Use
- Now time travel games can have their own form of terrorism or natural disaster. Yippee! The whole world can Go Mad From The Revelation.
- Justification for your Time Police to be real hardasses and never give second chances.
- For slapstick randomness or a surreal nightmare, set a game After The End, where Collapse of Causality has already happened (or kicks in real early). Characters would have variable pasts, with extremely fluid stats. The plot (and current reality) could be generated randomly every 15 minutes. My brain hurts already.