"A free energy principle for the brain". Friston, Kilner, Harrison (2006).
Figure 1: Schematic highlighting the difference between dissipative, self-organising systems like snowflakes and adaptive systems that can change their relationship to the environment.
Below is my rendition of the Figure, also inspired by the work of William Blake
Like any other scientific/artistic figure, a variety of interpretations and perspectives are possible & encouraged. Here is just one path through the “Winged Snowflake” drawing that highlights some core features of the Free Energy Principle and Active Inference.
Starting on the left side: The temperature arrow points down, pointing from lower temperatures (visually higher) to higher temperatures (visually lower). The phase boundary separates order from disorder; life from death. Above the phase boundary (below the critical temperature), crystalline and quasi-crystalline systems are able to persist, like a Snowflake in a freezing cloud. Below the phase boundary (above the critical temperature), to borrow a line from Hamlet, the Snowflake can do nothing but “melt, Thaw, and resolve itself into a dew” – it ceases to exist because it undergoes an irreversible phase transition. This dissipated system is symbolized by scattered raindrops, falling from a cloud.
On the top side of the phase boundary, a well-ordered Snowflake is represented as a Bayesian graph (nodes are statistical variables, edges are associations among node-variables). The Bayesian graph (map) of the Snowflake (territory) is a construction that represents the minimal Active Inference entity in terms of a partitioning with four kinds of nodes: Internal, External, Sense, and Action (see “Stochastic Chaos and Markov Blankets” and ActInf Livestream #032.0 for more information). External states influence Sense states, which influence the unfolding dynamics of Internal states (this is perception, or sentience). Internal states influence Action states, which Influence the unfolding dynamics of External states (this is action, or control). That's the perception-cognition-action cycle we know and love. The dots that were scattered widely below the phase boundary, are concentrated densely in the ActInf entity above the boundary.
Conditioned on the observation (map) and existence (territory) of the Snowflake, there are two options. First, the Snowflake can dissipate (the arrow pointing down to the raindrops). Or, the Snowflake can live (persist, persevere, survive, resist dissipation). Here, life is symbolized by a DNA double helix breaking out of the box (constrained open-endedness of development and evolution). Once the DNA is outside of the box, we see all the activities you'd expect a good lifeform to do: replication to make more DNA, transcription of DNA into RNA, and translation of that RNA into Protein. Together, the dynamic persistence of DNA, RNA, and Protein (and their colleagues such as carbohydrates, lipids, and vitamins) is symbolized by the eternal cosmic dance of the winged Ant Queen (Queens come from Queens and make more Queens). This Snowflake Queen has regular insect wings on her left side (your right) and an angel wing on her right side (your left). Also she has a tripartite Troika for an antennal set (this is like having a third eye, but for Ants).
As the top cursive caption suggests, in order to be persistAnt in an entropic world, the Snowflake Queen must carry out “dissipative exchange that precludes phase transition”. This vital exchange is not based upon merely intellectualized cognition. Rather it is predicated upon “action on the environment” – this is what distinguishes Active Inference from a host of other frameworks like Predictive Processing, and integrates it with areas like Ecological Psychology, Cybernetics, and Enactive/Embodied/Extended/Embedded/Encultured cognition.
All “things” do come to an end however, and the Ant Queen is no exception. When the particular Ant Queen loses her wings, she falls from grace and becomes worker-like. This phase transition for the Ant is like those raindrops falling from a frozen cloud – or not!