The first finding of our experiments with Galatea is that visual knowledge alone, with no explicit representation of causal knowledge, is sufficient for enabling analogical transfer. This validates the central hypothesis of our work. Galatea suggests a computational model of analogy based on dynamic visual knowledge that complements traditional models based on causal knowledge. Although Galatea does not address the issues of retrieval and mapping, put together with other work described in the previous section, we can now more confidently conjecture that visual knowledge alone can enable retrieval, mapping and transfer in analogy.
A second finding of our work on Galatea is that evaluation, in general, cannot be done using visual knowledge alone; it requires causal knowledge too. Thus visual knowledge enables only the steps that depend directly on the visual similarity between the target problem and the source analog, e.g., retrieval, mapping and transfer. It does not, however, fully support the evaluation step because it depends not on similarity but on the intrinsic causal and teleological structure of the target problem.
Galatea represents visual knowledge symbolically, in the form of symbolic images made of primitive visual elements and primitive visual transformations. The symbolic representation provides the standard benefits of discreteness, abstraction, ordering, and composition. Although sequences of lower-level bitmap representations also capture the notion of ordering, they, by themselves, neither capture abstractions that enable noticing visual similarity nor enable transformations on the images. This leads us to a third finding: Galatea provides additional evidence that symbolic representations of visual images are necessary for analogy.