  Although pretrained language models (PTLMs) have been shown to contain
significant amounts of world knowledge, they can still produce inconsistent
answers to questions when probed, even after using specialized training
techniques to reduce inconsistency. As a result, it can be hard to identify
what the model actually "believes" about the world. Our goal is to reduce this
problem, so systems are more globally consistent and accurate in their answers.
Our approach is to add a memory component - a BeliefBank - that records a
model's answers, and two mechanisms that use it to improve consistency among
beliefs. First, a reasoning component - a weighted SAT solver - improves
consistency by flipping answers that significantly clash with others. Second, a
feedback component re-queries the model but using known beliefs as context. We
show that, in a controlled experimental setting, these two mechanisms improve
both accuracy and consistency. This is significant as it is a first step
towards endowing models with an evolving memory, allowing them to construct a
more coherent picture of the world.
