  The eigenstate thermalization hypothesis (ETH) is a powerful conjecture for
understanding how statistical mechanics emerges in a large class of many-body
quantum systems. It has also been interpreted in a CFT context, and, in
particular, holographic CFTs are expected to satisfy ETH. Recently, it was
observed that the ETH condition corresponds to a necessary and sufficient
condition for an approximate quantum error correcting code (AQECC), implying
the presence of AQECCs in systems satisfying ETH. In this paper, we explore the
properties of ETH as an error correcting code and show that there exists an
explicit universal recovery channel for the code. Based on the analysis, we
discuss a generalization that all chaotic theories contain error correcting
codes. We then specialize to AdS/CFT to demonstrate the possibility of total
bulk reconstruction in black holes with a well-defined macroscopic geometry.
When combined with the existing AdS/CFT error correction story, this shows that
black holes are enormously robust against erasure errors.
