Figure 1.

Comparing micro to macro. (a) A biological micro-scale, here a set of ion channels opening and closing, which makes up the membrane potential. (b) A causal model, and abstraction of the workings of the system at the micro-scale, is created by the modeler or experimenter (generally via interventions). This causal model might represent the openings and closings of channels, or the interactions of other molecular interactions, and may have a very high number of parameters. (c) Biological systems often have available macro-scales which are some dimension reduction of the micro-scale. An example might be the membrane potential of a cell. Often these biological macro-scales have interventions that manipulate them directly, such as current injection to change the variables or states can only be manipulated at the macro-scale. (d) A macro-scale causal model is an abstraction, wherein each variable or element might represent that state of the macro-scale and the effects of changes of those states, like how increases the membrane potential might lead to further changes in neighboring cells.