This presentation proposes a new account of homology, which defines homology as a correspondence of developmental or behavioral mechanisms due to common ancestry. The idea is formally presented as isomorphism of causal graphs over lineages. The formal treatment not only clears the metaphysical skepticism regarding the homology thinking, but also provides a theoretical underpinning to the concepts like constraints, evolvability, and novelty. The novel interpretation of homology suggests a general perspective that accommodates evolutionary develop mental biology (Evo-Devo) and traditional population genetics as distinct but complementary approaches to understand evolution, facilitating further empirical and theoretical researches
