We present several epistemic views of ideation in scientific discovery that we have investigated: conceptual classification, abductive explanation, conceptual modeling, analogical reasoning, and visual reasoning. We then describe an experiment in computational ideation through model construction, evaluation and revision. We describe an interactive tool called MILA–S that enables construction of conceptual models of ecological phenomena, agent-based simulations of the conceptual model, and revision of the conceptual model based on the results of the simulation.   The key feature of MILA–S is that it automatically generates the simulations from the conceptual model. We report on a pilot study with 50 middle school science students who used MILA–S to discover causal explanations for an ecological phenomenon. Initial results from the study indicate that use of MILA–S had a significant impact both on the process of model construction and the nature of the constructed models.  We posit that MILA–S may enable scientists to construct, evaluate and revise conceptual models of ecological phenomena.