Causality still has meaning. For example, I can do something now that affects the past. That effect in the past can later cause something to happen in the future.
Time machines are fantasy, it is impossible within the laws of physics to design electronic technology that could travel in time. I did the math and it just doesn't work, it would implode every atom in your body as soon as it's turned on.
The logic of this test is equivalent to asking me for the winning lottery numbers. I can't answer a question that hasn't been asked yet.