Is time travel to the past possible?
The native record histories considered here order events by authenticated dependencies: a later read uses an earlier write. An acyclic history cannot contain a chain in which a record is its own strict predecessor. That excludes a grandfather-style contradiction within that construction. It does not prove that every spacetime allowed by general relativity has no closed timelike curve, or that a finite repair theorem settles all time-travel physics. OPH's complete-history closure is a different kind of loop: the recovered description and its realization agree on one whole history. It sends no signal to an earlier moment. Ordinary clocks, aging and relativistic time dilation can occur inside that history. Any stronger time-travel claim needs a physical spacetime reconstruction and its actual causal conditions.
See also Who wrote the laws if the universe reconstructs itself? (The bootstrap paradox), If reality is a fixed point, is everything predestined?, Why does the traveling twin come home younger?
Also in Chapter 7: Why Is There No Such Thing As Now?.
This answer comes from OPH, Observer Patch Holography. OPH is a rigorous, consistent and complete description of the unified, self-creating computational Universe we inhabit. Its consistency is machine-checked: the fixed point at its core is constructed explicitly, and a theory with a model contains no contradiction.
To understand OPH and check every step yourself, start with the free book Reverse Engineering Reality. It builds the theory from the ground up, and the OPH Notebook answers your questions while you read.
read the free bookask the notebookor ask sage:read chapter 16: Why Does Time Run, and Only One Way?watch a universe make its own particles