  Causal discovery is at the core of human cognition. It enables us to reason
about the environment and make counterfactual predictions about unseen
scenarios that can vastly differ from our previous experiences. We consider the
task of causal discovery from videos in an end-to-end fashion without
supervision on the ground-truth graph structure. In particular, our goal is to
discover the structural dependencies among environmental and object variables:
inferring the type and strength of interactions that have a causal effect on
the behavior of the dynamical system. Our model consists of (a) a perception
module that extracts a semantically meaningful and temporally consistent
keypoint representation from images, (b) an inference module for determining
the graph distribution induced by the detected keypoints, and (c) a dynamics
module that can predict the future by conditioning on the inferred graph. We
assume access to different configurations and environmental conditions, i.e.,
data from unknown interventions on the underlying system; thus, we can hope to
discover the correct underlying causal graph without explicit interventions. We
evaluate our method in a planar multi-body interaction environment and
scenarios involving fabrics of different shapes like shirts and pants.
Experiments demonstrate that our model can correctly identify the interactions
from a short sequence of images and make long-term future predictions. The
causal structure assumed by the model also allows it to make counterfactual
predictions and extrapolate to systems of unseen interaction graphs or graphs
of various sizes.
