Feb 7, 2025
Say we take predictive coding seriously and accept that the chief goal of a human is minimizing prediction error. Does this imply anything useful about how we should live our lives? Can we use beautiful concepts from the intersection of neuroscience and deep learning to write pithy new self-help books? I think we can.
(If you’re not sure what predictive coding is, read Scott’s post about it first, I promise it’s excellent).
Your body’s chief objective is maintaining homeostasis - being not too cold, but not too hot, not too hungry, but not too full, keeping blood pressure not too low but not too high, and so on, staying in the narrow range of parameter combinations which are conducive to life. In predictive coding we could phrase this as a) having a prediction that we’re in this ideal state and b) trying to minimize prediction error (deviations from this ideal state). In a sense, you are just a very complicated thermostat.
I think some interesting advice comes from taking this literally: trying to be a good thermostat, consciously helping your body stay in its sweet spot.
Most obviously, almost tautologically: you want to be good at noticing when things are off and knowing how to adjust them. You should consciously practice the process of iteratively feeling out what temperature, trying something to get closer to perfect homeostasis, repeating. You can do this at multiple levels.
For example: in what ways is your body uncomfortable at this moment? How could you nudge your posture in the direction of being more comfortable? Given some particular feedback from your body (a specific kind of soreness or discomfort or urge to move) what can you do to relieve it? What does it feel like when you’re moving in the right direction, when you successfully get more comfortable or stretch out a sore muscle? See here for more along this line of thought.
Or you could do something similar with food, trying to feel into how a given food makes you feel, getting good at listening to what your body wants. Potentially you should meditate to increase your sensory clarity, to get more accurate feedback and correct more quickly.
I think this idea of low-level tuning and conscious equilibrium-seeking is good advice and interesting and underrepresented in mainstream self-help ideas. But we can also approach the “bigger” things in life from this frame.
In the same way homeostasic mechanisms make you eat when you’re hungry, higher level predictions about what kind of person you are and how your life is going shape your life trajectory. So you could try to consciously help the error-minimization process on this level too, checking what expectations you have about your life, about your purpose and meaning and fulfillment and success in relationships, and aligning these expectations with how your life is going. You could ask yourself: In what ways is your life direction misaligned with what you feel it should be? In what ways are you not living up to your expectations? What things do you keep doing that some part of you feels are bad?
But well, the problem here is that the thermostat/predictive coding perspective is often too low level to give actionable advice here. What it tells you is almost trivially true - sure, I’m a prediction error minimization machine, but that’s not very helpful way to think when picking a career (will a doctor or a programmer experience less prediction error? I don’t know!) So naturally you want some kind of higher level heuristics - i.e. boring old life advice which it’s also not always obvious how to follow, like “follow your passion” or “get a good career”.
If the thermostat framing still offers some advice here, I think it’s something like: take seriously the project of figuring out where you are in life and what you want. Contemplate this deeply and without prejudice: your world model / set point is probably a hacky mess and includes parts which are silly (like a stuck prediction that you’re an astronaut) or which you find distasteful (repressed dark sexual urges). Try to untangle this mess through some kind of intentional meditation practice, either adjusting your beliefs or taking actions in the world to change your life. Taking a step in the direction of perfect homeostasis will involve some things getting better and some getting worse. This is normal; have faith in the power of gradient descent through high-dimensional spaces.
An important thing to understand is that in these more non-trivial cases, you really have two levers to pull: you can change your beliefs to match reality, or change the world to make your beliefs come true. The important thing is the alignment between expectation and reality.
More speculatively, I think this is a good argument for following some kind of Holy Book, be it the Bible or the Bhagavad Gita or How to Win Friends and Influence People or whatever. People have the urge to take advice from books piecewise, trying to take the good and leave the bad. But if you adopt the whole thing, that’s likely a nicely internally consistent set of beliefs, and by adopting it somewhat axiomatically you simplify the problem of deciding whether to change beliefs or to change behavior - you usually change behavior. Maybe even having a mediocre book as your Holy Book is better than nothing for achieving this alignment.
This is much harder than you think.
First, because changing beliefs is generally difficult, and completely refactoring all your beliefs is tremendously difficult, to the extent that becoming Good within your current understanding of it is actually easier.
Second, because your beliefs are tied up with other beliefs which are hard-coded. If you don’t eat for a while you will get hungry, good luck believing you’re not. Similarly, your desire for social approval and physical touch and sex are also difficult to manually override. But your complex beliefs are “grounded” in these hard-coded beliefs! You want a good career because you think then people will respect you, which will give you social validation, which you want because it’s associated with opportunities for sex, which is associated with physiological/chemical processes which you are basically wired to want. In reality this chain is some complicated chain of uninterpretable black-box Bayesian inferences, but the result is the same: it’s difficult to wirehead yourself into being deeply content with your life.
I must confess, what I’m trying to do with this blog post has already been done very well by a 1960 self-help booked called Psycho-Cybernetics. It phrases similar concepts in terms of your self-image – basically your self-fulfilling-prophecy about what kind of person you are – and claims that to achieve what you want you have to adjust your self-image so that it’s naturally guiding you towards it. I think of this in terms of moving your personality out of a local optima, or changing your beliefs about yourself for the better (with “better” being somewhat objective here, due to the hard-coded prediction errors mentioned previously) - see also this excellent blog post about personality formation.
I think the most interesting takeaway from Psycho-Cybernetics is the emphasis on mental/physical relaxation combined with visualization. This is practical advice on how to adjust your priors! You do a body scan muscle relaxation thing and then try to concretely visualize your desired outcome. And then, importantly, over the following days/weeks/months you let your prediction-error reduction “steering” mechanism naturally guide you, you don’t need to do much consciously other than trying not to get in the way.
The book is generally very good - if you think this line of thought is interesting I recommend it as a kind of practical treatment of the “how” of modifying your beliefs for the better. Curiously, its self-image adjustment idea rhymes a lot with the idea of manifesting, and maybe with what hypnotherapists do.