Amazing guy.
> He suddenly became possessed by a thought that has never let go of him since. “There must be a way of understanding everything by starting from nothing,” he thought. “If I’m only allowed to start off with one point in the entire universe, can I derive everything else I need from that?” He stayed there on his bed for hours, making his first attempt. “I failed completely, obviously,” he says.
> Robert ruminated obsessively about, of all things, angel shit; he pondered whether the stuff was a blessing or a curse and whether it was ever visible to the eye, and he seemed perplexed that these questions had not occurred to others. To Friston, the very concept of angel shit was a miracle.
> Over time, Hinton convinced Friston that the best way to think of the brain was as a Bayesian probability machine. The idea, which goes back to the 19th century and the work of Hermann von Helmholtz, is that brains compute and perceive in a probabilistic manner, constantly making predictions and adjusting beliefs based on what the senses contribute. According to the most popular modern Bayesian account, the brain is an “inference engine” that seeks to minimize “prediction error.”
How are neighborhoods like neural nets? How are they not like neural nets? How can they become more like neural nets?
Free energy principle Wikipedia 
> Markov blanket, which in machine learning is essentially a shield that separates one set of variables from others in a layered, hierarchical system. The psychologist Christopher Frith—who has an h-index on par with Friston’s—once described a Markov blanket as “a cognitive version of a cell membrane, shielding states inside the blanket from states outside.”
> a free energy agent always generates its own intrinsic reward: the minimization of surprise. And that reward, Pitt says, includes an imperative to go out and explore.
> Friston, who told him that the same math that applies to cellular differentiation—the process by which generic cells become more specialized—can also be applied to cultural dynamics. “This was a life-changing conversation