An alternative is to conjecture that, while time travel is possible, it never leads to paradoxes ; this is the Novikov self-consistency principle.

The Novikov self-consistency principle, also known as the Novikov self-consistency conjecture, is a principle developed by Russian physicist Igor Dmitriyevich Novikov in the mid-1980s to solve the problem of paradoxes in time travel, which is theoretically permitted in certain solutions of general relativity ( solutions containing what are known as closed timelike curves ).

: We shall embody this viewpoint in a principle of self-consistency, which states that the only solutions to the laws of physics that can occur locally in the real Universe are those which are globally self-consistent.

This could mean that the Novikov self-consistency principle does not actually place any constraints on systems outside of the region of spacetime where time travel is possible, only inside it.

: The simplest way to impose the principle of self-consistency in quantum mechanics ( in a classical space-time ) is by a sum-over-histories formulation in which one includes all those, and only those, histories that are self-consistent.

The Novikov self-consistency principle states that a time traveller would not be able to do so.

In this example, it must always have been true that the people were rescued by a time traveller and replaced with realistic corpses, and there would be no " original " history where they were actually killed, since the notion of changing the past is deemed impossible by the self-consistency principle.

However, the Novikov self-consistency principle is intended to go beyond just the statement that history must be consistent, making the additional nontrivial assumption that the universe obeys the same local laws of physics in situations involving time travel that it does in regions of spacetime that lack closed timelike curves.

The principle of self-consistency is intended to rule out such behavior.

In essence, the principle of self-consistency is a principle of no new physics.

If one is inclined from the outset to ignore or discount the possibility of new physics, then one will regard self-consistency as a trivial principle.

Time loop logic, coined by the roboticist and futurist Hans Moravec, is the name of a hypothetical system of computation that exploits the Novikov self-consistency principle to compute answers much faster than possible with the standard model of computational complexity using Turing machines.

In this system, a computer sends a result of a computation backwards through time and relies upon the self-consistency principle to force the sent result to be correct.

The self-consistency principle guarantees that the sequence of events generating the paradox in the nested conditional has zero probability.

Claims, arguments, or philosophical principles logically equivalent to the Novikov self-consistency principle have been published before Novikov's own publication.

* The events of the first Terminator film appear to respect the self-consistency principle.

" While this may be an example of the self-consistency principle, it is not entirely clear whether the original time-line was one in which Hitler died in the bunker, or whether the traveler succeeded in changing history.

* From wormhole to time machine: Comments on Hawking's Chronology Protection Conjecture, which also addresses the Novikov self-consistency principle

The Novikov self-consistency principle and Kip S. Thorne expresses one view on how backwards time travel could be possible without a danger of paradoxes.

Another resolution, of which the Novikov self-consistency principle can be taken as an example, holds that if one were to travel back in time, the laws of nature ( or other intervening cause ) would simply forbid the traveler from doing anything that could later result in their time travel not occurring.

It became the sole `` subject '' of `` international law '' ( a term which, it is pertinent to remember, was coined by Bentham ), a body of legal principle which by and large was made up of what Western nations could do in the world arena.

For better or for worse, we all now live in welfare states, the organizing principle of which is collective responsibility for individual well-being.

Whether a concept analogous to the principle of internal responsibility operates in a nation's external relations is less obvious and more difficult to establish.

) The concept of nationalism is the political principle that epitomizes and glorifies the territorial state as the characteristic type of socal structure.

Complementing the political principle of nationalism is the legal principle of sovereignty.

As Lipton puts it: `` The Eros is felt in the magic circle of marijuana with far greater force, as a unifying principle in human relationships, than at any other time except, perhaps, in the mutual metaphysical orgasms.

But Aristotle kept the principle of levels and even augmented it by describing in the Poetics what kinds of character and action must be imitated if the play is to be a vehicle of serious and important human truths.

So far as the existing body of formal principle and procedure is concerned, categorical novelties are not to be anticipated in Jewish-Gentile relationships ; ;

In conformance with the maximization principle we affirm that Gentile-Jewish relations will be harmonious or inharmonious to the degree that one relation or the other is expected by the active participants to yield the greatest net advantage, taking all value outcomes and effects into consideration.

Like ours, the economy of the space merchants must constantly expand in order to survive, and, like ours, it is based on the principle of `` ever increasing everybody's work and profits in the circle of consumption ''.

The principle is commendable but we suspect that in the practice somebody is going to get gulled.

In the United Nations Charter, the right of self-determination is also an essential principle.

Nonetheless, although few in number they are a stubborn crew, as tenacious of life as the Hardshell Baptists, which suggests that there is some kind of vital principle embodied in their faith.

What we will be sacrificing in any such arrangement will be our power to be selective which is contained in the reciprocal trade principle under which we now operate.

A second fundamental principle is that involved particularly in the present proceeding -- the difference between nighttime and daytime propagation conditions with respect to the standard broadcast frequencies.

In following this general principle, Mason provides the observer with a natural eye progression from foreground to background, and the illusion of depth is instantly created.

The principle of `` bills only '', or `` bills preferably '', seems so strongly accepted by the Federal Reserve that it is difficult to envision conditions which would persuade the authorities to depart radically from it by extending their open market purchases regularly into long-term Government securities.

In fact, some -- Anzilotti is the principle example -- went so far as to say that all international law could be traced to the single legal norm, Pacta sunt Servanda.

Obviously, the goal here proposed is the guiding principle in Mr. Justice Frankfurter's opinions -- to the extent that Congress leaves the problem to judicial discretion.

Mr. Justice Black no doubt concurs in principle but is more apt to make exceptions to achieve a generous and `` just '' result.

It is an accepted juridical principle in California that a Superior Court decision does not constitute a binding legal precedent.

Logically, then, the first principle of the plan must be that it is not rigidly oriented toward any geographical area.

Therefore the second principle of the plan must be that, while providing for all-out hostilities, its effectiveness is not dependent on general war.