Proceedings of the Annual Meeting of the Cognitive Science Society

Structural models provide an important source of hypothetical knowledge in scientific discovery. Informal Qualitative Models (IQMs) are structural models which can be applied to weak theory scientific domains. Example models are presented for the domain of solution chemistry. These models can be systematically generated, but, due to the weak theory nature of the domains to which they are applied, they cannot be verified directly. Instead, the application of IQMs to a problem can be used to drive other scientific discovery processes; in particular, the discovery of numeric laws. The HUM E system is a discovery system based around the application of IQMs. HUME's discovery goal is to construct explanations for phenomena, such as the depression of the freezing point of salt solutions, using a variety of reasoning strategies. HUM E first attempts to explain such phenomena using a pre-existing theory. If this theory is not able to provide an explanation, the system uses a combination of theory construction and numeric law discovery. The application of IQMs provides hypotheses for use by the other two processes. Used in this way, IQM application can be seen to provide a degree of explanatory support for numeric laws which would otherwise be simply descriptive generalisations of data. An example of the application of HUM E to a problem in solution chemistry is presented.