Abstract: In second and first millennium BCE Mesopotamia, the texts most commonly associated with the practice of divination are omen lists written in Babylonian. These texts are a still largely unexplored source of information on ancient Mesopotamian scribal creativity and on scribal strategies for the production of meaning and knowledge. Focusing on sequences of interrelated omens, the paper will demonstrate that the interplay of similarity and contrast between contiguous or near-contiguous textual elements is a major force in the process of text production in omen lists. In analysing the step-by-step unfolding of these omen sequences, I will discuss how ancient Mesopotamian scribal creativity gave shape to a system of knowledge production characterized by the gradual refinement of concepts through the incremental addition of qualifications – based on the power of similarity, parallelism and analogy. Thus, a principle of ‘repetition with variation’ allowed Babylonian diviners to understand their world through analogical reasoning. In conclusion, I will argue that this principle is in fact a pervasive means of constructing and structuring Mesopotamian erudite compositions in general. This approach makes a crucial aspect of Ancient Mesopotamian intellectual history amenable to cross-cultural comparison.