Building blocks is used here as a synonym for the components or parts that interact to produce the phenomenon of interest. Components interact in ways to form mechanisms that produce or maintain the phenomenon. Identifying building blocks (or components) that seem to be interacting to produce the behavior of interest is the first step in generating an explanation. A mechanistic explanation, however, must go beyond identifying components to explain how the components interact to produce the phenomenon. Researchers can then test this theoretical explanation by manipulating the components via modeling or experimentation.
Because building blocks are equivalent to components in mechanistic explanations, further discussion of their role is offered in the entry on mechanisms.