# Black Hole Complementarity and Violation of Causality

## TL;DR

This paper demonstrates that black hole complementarity, aimed at preserving information, can lead to causality violations through a hypothetical device that transfers information from the future to the present.

## Contribution

It reveals a potential causality violation inherent in black hole complementarity by proposing a hypothetical device based on BHC.

## Key findings

- Black hole complementarity can violate causality.
- A hypothetical device could transfer information from future to present.
- BHC may conflict with fundamental causal principles.

## Abstract

Analysis of a massive shell collapsing on a solid sphere shows that black hole complementarity (BHC) violates causality in its effort to save information conservation. In particular, this note describes a hypothetical contraption based on BHC that would allow the transfer of information from the future to the present.