Much has been made in science fiction of time-travel paradoxes and speculations on how history would be altered by the mere act of time-travel. Although, since none of my time-machines have worked as planned I have had little practical need to contemplate such things.
However, it has occurred to me that we are all time-travellers of a sort, and as such exercise a sort of agency on the outcome of future events. The implication of this, and the other thing about science-fiction time-travel, is that there should be a general reference guide of causative actions that can be referenced to minimize (or maximize) our chronological footprints.
This would be a purely scientific undertaking, using rigorous experimentation to gauge the precise worldly impact of any given action. What effect the actions have on the individual actor are not necessarily important, only the more general effects.
Possible experiments include crushing a single ant, sending a butterfly aflutter, and even to social interactions such as ordering a coffee, or chatting with a stranger. From such experiments the scope and scale of the action is quantified with regard to its uppermost and lowest limits.-- rcarty, Dec 18 2011 I'd sign up for a benevolent chronological-footprint- maximizing service, if it worked.-- sninctown, Dec 18 2011 On a physically practical side, this would sort of be a ratings book for random-acts-of-kindness, possibly with a few anecdotal tales of how X small (or large) act changed someone's life for the better.
On a speculative side, this could be crushed by certain science-fiction factors. What if this is a universe where Novikov self-consistency holds true and thus the past cannot be changed, making the rigorous experimentation impossible?
Either way, brilliant idea.-- Hive_Mind, Dec 18 2011 There is an article on this very subject in one of the latest Scientific American mags. It was a good read.-- 2 fries shy of a happy meal, Dec 18 2011 How do you interpret such experiments without a control?-- ldischler, Dec 18 2011 // How do you interpret such experiments without a control? //
By labeling them 'experiences' instead.
I believe that it is impossible to change one's own present by altering the past. By the very act of traveling back in time, much less whatever actions they undertake there, the traveler has induced a change in that chrono- spatial paradigm. This has the same result as each action we take in the present: generation (or activation, depending on your school of thought) of a divergent timeline. This timeline goes off in a different direction while our timeline remains as it was (minus one now- stranded time traveler) because, and this is the important bit, _it already happened_.
This theory (which I am sure is not strictly my own) effectively negates the causality problem, jahvol?-- Alterother, Dec 18 2011 Re: control. Again, not much thought into this one, but I assumed since these were to be scientific experiments that the control would be a similar situation without the agency of a single actor acting upon it. If I were a time traveler what could I get away with without affecting history? Could I buy a coffee? How much extra effect does one person have? How long does it take? 5 mins. Are social bonds formed during the interaction? No. How many people are behind you? Maybe let them go first. How many people are in front of you, is the line already long? More people would suggest your single action is making less impact ie. preventing the cashier from getting asked out on a date by the customer etc. or making someone late for an important meeting. Do you look at the cashier when you order, or do you look at the menu, her breasts? Each of these will be studied for effect. Intuitively looking at menu would probably by the least reactive. Even without knowing what would have happened otherwise this scale can prevent you from changing what would have other wise happend.-- rcarty, Dec 18 2011 Only by knowing, down to the sub-atomic scale, everything occurred in the original paradigm could a true scientific control be established, and if we knew, that knowledge would contaminate the experiment. The only way I can envision causality experiments working would be by using virtual models, and as Adams pointed out, it would take a computer the size of a planet to monitor all of the variables involved.-- Alterother, Dec 19 2011 The idea for this scale has already been half-baked. However, I shall not take you to task for not finding it, since I have been unable to re-find it. As I remember, it was a short story in Analog, or some-such from late 60's or early 70's.
Quick synopsis:An extremely powerful alien race is observing, but not interfering with, other races - including earth. A couple of their low-level operatives get into an argument over how "non-interfering" an interaction has to be in order to actually not have an effect, and end up with one operative betting the other that he can produce a "Class 1" (world-altering) effect with a "Class 5" (utterly trivial) influence.
The "trivial" influence is that an agent gives a particular American physicist the idea of changing the spelling of his name by one letter, from a Russian spelling to a more Anglicised version. This attracts the attention of intelligence agencies, whose paranoia requires them to find out what he's hiding. Turns out his work (unbeknownst to the physicist) had some applications toward force-fields; development on those lines attracts Soviet interest, with the final result that all vulnerable areas on Earth end up shielded - precluding any possibility of nuclear war.
In the denouement, the bet-losing operative, reluctant to pay up on the bet, remarks how much trouble the winner is going to be in when the bosses find out. The winner offers a double-or-nothing bet that, with another "Class 5", he can reverse the effect...-- lurch, Dec 19 2011 random, halfbakery