how to use a time machine

or, the best of all possible worlds

"The time machine has probably been invented hundreds of times," the Speaker told the assembled masses. "But the genius, the independent inspiration that I believe is mine alone, is the realization of how it works." Predictably, the throngs cheered.

"Why nobody realized the true power of the paradox is beyond me," he told the Fairest Of Them All. "But it was simple enough to implement." She swooned. A man of his power in another situation might doubt his concubine's sincerity, her interest or her intentions, but he knew that wasn't necessary.

"Once I realized I would do anything to have a time machine," he told his reflection in the shaving mirror, "I began to believe I would never have one. After all, would I not immediately have used it to improve my past?" The razor completely failed to nick his skin. "Why had I not met my future self?"

"It is," he told the assembled International Temporal Physics Symposium, "because the device is impossibly simple. Three-axis rotation causes precession in the fourth. Only, most accidental discoverers would never notice the effect, because causality holds. The future is impossibly broad. Literally anything could happen. In the past, though, the one certainty is that it is impossible to meet yourself."

"If you travel to the past, you will certainly influence yourself. From the traveller's perspective, as soon as you leave you will cease to exist." The Illuminati nodded, appreciatively.

The Speaker rose in summation, his diction perfect, his voice projecting beautifully. "I do not fear your knowledge of these facts. Were you each to find your own alternate, perfect timeline, mine would remain as it is..."

"But you must now forgive me," he told his weeping empress. "Before it is too late, there is but one thing I must amend."