The consequences of time travel
Lets go back to the time travel communication model. Imagine that future scientists will develop a device that can broadcasts messages to the past, allowing potential prophets to 'hear' these messages in their head. Although this - time machine - might function correctly, the question is whether you can reliably test such a device. And use experiments to scientifically proof the underlying theory.
In science to prove a theory you need to be outside of the closed system where the experiment is conducted to be able to be objective. If this is not possible than no valid proof can be obtained from experimenting. One cannot test for effects and results to a closed system from within. Further more an experiment can not be repeated as the environment cannot be completely re-set. Effects of former experiments will stay inside the closed system, contaminating further experiments.
The first thought that comes up, is that with any form of time travel no one can get outside the 'test-tube'. This also applies to sending messages to the past. The prophet (receiver) is the test rabbit but - unavoidable - so are the scientists (the sender). Since all are part of the same communication model and experiment, the outcome of an experiment will affect all parties. What is therefore missing is an absolute base line to measure against. This base line represents a history time line without the interference of time travel experiments.
Since an experiment typically exists in sending a message to the past, it would be interesting to theorize, what would be considered to be a good or bad message and what are the rules for a good message?
It seems that the consequences of a changed past mainly concerns the sender.
A change caused by a message will affect the future of the receiver. In general people feel that the future is not fixed and that they have free will to shape their own, although they know that they are not in complete control.
If time travel and the technology of sending messages back to the past really gets developed it will lead to different opinions between scientists regarding the consequences and side effects of experiments.
The first controversy has to do with the relationship between the future of the receiver and the past of the sender. How does a change caused by the message affect the present time of the sender? The second disagreement has to do with the relationship between causality and chronological events. The: 'What comes first question'.
About the relationship between the two times, there are different ideas. Up to now we have taken for granted that both are related in such a way that a change in the past due to the message will also affect the present time of the scientists. But this is not certain.
Even if there would be a direct relationship, then this will be very hard to prove. The difficulty being, that the sender might not notice any changes, since he is also inside the closed system he would be equally affected by the experiment.
The question whether an experiment can cause consequences in the 'world' of the sender might lead to several schools of thinking:
Reject the idea that an experiment can change their own past, present or future.
Believe that changing the past with a time travel experiment causes consequences for their own present time.
Might be convinced that communication is possible, but doubt that there can be any consequences for them.