Just when you thought you understood how the world works, the tachyons come to shake things up.

For those who haven't heard by now, the masterminds at CERN who brought you the LHC rap have made what might be one of the most important discoveries of our age: that subatomic particles - neutrinos - can travel faster than the speed of light. It's a small effect - 60 nanoseconds faster - but it still appears to be faster than Einstein's proposed barrier of 186,282 miles (299,792 kilometers) per second.

Einstein's special theory of relativity proposes that nothing in the universe can travel faster than the speed of light. Remember E = mc²? The constant "c" in that famous equation is the speed of light in a vacuum and a "fundamental feature of the way space and time are unified." His theory is the basis of most everything in modern physics. And even though it's been validated by observation often, it still remains a theory.

If the results of this experiment are accurate, although it doesn't change reality, it changes some of the fundamentals we thought we understood about reality. (Well, you still can't divide by zero.)

This isn't the first time we were aware of this potential, but CERN's instrumentation is much more accurate than the prior discoveries. CERN doesn't want to believe it and they think it's premature to jump to conclusions. They've tried to find their error. They've looked for instrumental issues. They've been trying to figure it out for months. Everything seems to be in order. So now they are required by their ethics to put their measurement evidence out to the scientific community at-large to review, scrutinize, and evaluate.

What are some potential implications? For example, time is calculated using the speed of light. If you can go faster than the speed of light, you could potentially "outrun" time (ala the mythical faster-than-light tesseract from A Wrinkle in Time - yes, we're talking about time travel). Causality might not be accurate, for it functions within time (i.e., cause precedes effect). Imagine a world where effects occur before their causes. Those who believe in fate or destiny already do. The physics joke goes like this: The barman said: "Sorry, we don't serve neutrinos." A neutrino enters a bar.

But now to our point...

Philosophers are sometimes accused of mental masturbation - debating topics without any practical value. Science is implied to be the primary, rational method for understanding the nature of the world. But, whereas science thought (and still thinks) that there is a boundary on speed, maybe the CERN results suggest that new models are needed to understand how reality works.

New models describing reality might require new reasons to use them. Philosophy can be of practical use here. Philosophy can help us determine for what application our new understanding of reality should be applied. Philosophy can help us choose the reasons to apply our new knowledge. If speed is no longer a constraint, philosophy can be used to help direct us how best to use that faster speed. Science explains how reality works. Philosophy helps us decide what to do in reality and why we should do it.

What purpose does breaking the speed of light serve without philosophy? How can philosophy compliment this potential discovery? Does philosophy precede physics? What should philosophers be considering if the speed of light is not a constraint of reality? Why would this discovery be important? What are the philosophical implications if the future can affect the present? What impact does this have on the determinism vs. free will debate relative to morality? Should philosophers not even consider the implications of going faster than light with an assumption that another theory explains the results?

Sometimes also called retro-causation. A common feature of our world seems to be that in all cases of causation, the cause and the effect are placed in time so that the cause precedes its effect temporally. Our normal understanding of causation assumes this feature to such a degree that we intuitively have great difficulty imagining things differently. The notion of backward causation, however, stands for the idea that the temporal order of cause and effect is a mere contingent feature and that there may be cases where the cause is causally prior to its effect but where the temporal order of the cause and effect is reversed with respect to normal causation, i.e. there may be cases where the effect temporally, but not causally, precedes its cause.

The idea of backward causation should not be confused with that of time travel. These two notions are related to the extent that both agree that it is possible to causally affect the past. The difference, however, is that time travel involves a causal loop whereas backward causation does not. Causal loops for their part can only occur in a universe in which one has closed time-like curves. In contrast, backward causation may take place in a world where there are no such closed time-like curves. In other words, an ordinary system S taking part in time travel would preserve the temporal order of its proper time during its travel, it would keep the same time sense during its entire flight (a watch measuring S's proper time would keep moving clockwise); but if the same system S were to become involved in a process of backward causation, the order of its proper time would have to reverse in the sense that the time sense of the system would become opposite of what it was before its back-in-time travel (the watch will start to move counter-clockwise). So neither backward causation nor time travel logically entails each other and time travel is distinct from back-in-time travel...

A general notion of backward causation raises two sets of questions: those concerning conceptual problems and those that relate to empirical or physical matters. Among the first sets of questions that require a satisfactory answer are the following:

(i) Can metaphysics provide a notion of time that allows that the effect precede its cause? A proper notion of backward causation requires a static account of time in the sense that there is no objective becoming, no coming into being such that future events exist on the par with present and past events. It means that the future is real, the future does not merely consist of unrealised possibilities or even nothing at all. Ordinarily we may think of the past as a nothing that once was a something. But when asked what makes sentences about the past true or false, we would probably also say that it is the facts of the past that make present sentences about the past either true or false. The fact that I went to the cinema yesterday makes it true today when I say that I went to the cinema yesterday. This view is a realist one with respect to the past. If backward causation is to be conceptually possible it forces us to be realists with respect to the future. The future must contain facts, events with certain properties, and these facts can make sentences about the future true or false. Such a realist account is provided by static and tenseless theories of time. A static theory holds that the participation of time into the past, the present and the future depends on the perspective we human beings put on the world. The attribution of pastness, presentness and futureness to events is determined by what we take to exist at times earlier than and times later than the time of our experience.

(ii) Does backward causation mean that a future cause is changing something in the past? Even most protagonists consider it an unwarranted consequence that the notion, if true, involves the idea that the future is able to change the past. Their answer has therefore usually been that if we have the power to bring something about in the past, what came about really already existed when the past was present. We have to make a distinction between changing the past so it becomes different from what it was and influencing the past so it becomes what it was. A coherent notion of backward causation only requires that the future is able to have an influence on what happens in the past.

(iii) Can the cause be distinguished from its effect so that the distinction does not depend on a temporal ordering of the events? The adherents have usually tried to give an account of causation in which the cause and the effect are not seen as regularities between types of events. What is required is some account of the direction of causation which does not rely on the direction of time. Various alternative proposals refer to counterfactuals, probabilities, agents, manipulation and intervention, common cause or causal forks. It is, apparently, only a Humean notion of causation that needs the temporal identification of the cause and the effect. But there are also problems with some of the other accounts; for example, the Stalnaker-Lewis theory of counterfactual has difficulties with backtracking counterfactuals and backward causation because if c occurs later than e, the proposed method of truth evaluation assumes that e occurs in the relevant possible worlds in which c does not occur. In general, the assessment of a counterfactual conditional is carried out by assuming that the possible world should be identical with the actual world up to c; therefore, it is stipulated that the closest possible world is one in which everything happens just as in the actual world up to the time of c's occurrence which means, given e occurs before c, that it will include the occurrence of e. But then it is necessarily true that there is never a possible world closer to the actual world which includes c but not e. This creates a problem because we consider any causal connection between c and e as contingent.

(iv) Can the bilking argument be challenged in such a way that the mere possibility of intervention does not generate any serious paradoxes? The force of the bilking argument can, it seems, be weakened in various ways. First, one may hold that it is not a problem for our notion of backward causation that we can in principle intervene in the course of the events. If we actually do so and prevent A after B has occurred, then of course a particular later A (which does not exist) cannot be the cause of a particular earlier B (which exists). But in all those cases where nobody actually intervenes, events of the same type as A may be the cause of events of the same type as B. This is not different from what can happen in some cases of forward causation. Assume that P causes Q in the relevant circumstances. We may still prevent a particular P from happening, but at the same time a particular Q may nevertheless occur because in the given circumstances it is caused by another event than P. Second, if a later event A really causes an earlier one B, then it would be impossible to intervene into the cause of the event after B has happened and therefore impossible to prevent A from happening. If someone tries, she will by all means fail. It may intuitively sound strange as long as we think of backward causation as consisting of something we can control directly by our everyday actions. But if backward causation is a notion that is applicable only to processes that human beings are unable to control in any foreseeable way the notion would not provoke our intuitions so much.

Backward Causation

DISCUSS!

Original posting by Braincrave Second Life staff on Sep 26, 2011 at http://www.braincrave.com/viewblog.php?id=651