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essential variables are physiological quantities, such as body temperature, sugar levels, oxygen levels, and the like, that must be kept within certain rather strict limits in order for an organism to remain alive.
The experience of fear I feel as a bear approaches is a control-oriented perception of my body—more specifically “my body in the presence of an approaching bear”—that sets off a series of actions that are best predicted to keep my essential variables where they need to be.
The control-oriented perceptions that underpin emotions and moods are all about predicting the consequences of actions for keeping the body’s essential variables where they belong. This is why, instead of experiencing emotions as objects, we experience how well or badly our overall situation is going, and is likely to go.
This is where we reach the core of the beast machine theory: the proposal that conscious experiences of the world around us, and of ourselves within it, happen with, through, and because of our living bodies.
Evolutionarily speaking, brains are not “for” rational thinking, linguistic communication, or even for perceiving the world. The most fundamental reason any organism has a brain—or any kind of nervous system—is to help it stay alive, through making sure that its physiological essential variables remain within the tight ranges compatible with its continued survival.
Allostasis means the process of achieving stability through change, as compared to the more familiar term “homeostasis,” which simply means a tendency toward a state of equilibrium. We can think of interoceptive inference as being about the allostatic regulation of the physiological condition of the body.
All of our perceptions and experiences, whether of the self or of the world, are inside-out controlled and controlling hallucinations that are rooted in the flesh-and-blood predictive machinery that evolved, develops, and operates from moment to moment always in light of a fundamental biological drive to stay alive.
For example, my body temperature is predicted to be rather constant over time, which—according to active inference—is why it actually turns out this way.
To put it another way: for as long as we live, the brain will never update its prior belief of expecting to be alive.
We will be better able to maintain our physiological and psychological identity, at every level of selfhood, if we do not (expect to) perceive ourselves as continually changing. Across every aspect of being a self, we perceive ourselves as stable over time because we perceive ourselves in order to control ourselves, not in order to know ourselves.
I proposed that to be useful for the perceiving organism, our perceptual best guesses need to be experienced as really existing out there in the world, rather than as the brain-based constructions that in truth they are.
The same reasoning holds for the self too. Just as it seems as though the chair in the corner really is red, and that a minute really has passed since I started writing this sentence, the predictive machinery of perception when directed inwardly makes it seem as though there really is a stable essence of “me” at the center of everything.
In particular, the hard-problem-friendly intuition that the conscious self is somehow apart from the rest of nature—a really-existing immaterial inner observer looking out onto a material external world—turns out to be just one more confusion between how things seem and how they are.
For Friston, the free energy principle explains all features of living systems,
entropy as a measure of disorder, diversity, or uncertainty. The more disordered a system’s states are—like an ink drop dispersed messily throughout the water—the higher the entropy.
In physics, the second law of thermodynamics tells us that the entropy of any isolated physical system increases over time.
According to the FEP, for a living system to resist the pull of the second law, it must occupy states which it expects to be in. Being a Good Bayesian, I’m using “expect” in a statistical sense,
For any living system, the condition of “being alive” means proactively seeking out a particular set of states that are visited repeatedly over time, whether these are body temperatures, heart rates
Ultimately, all organisms—not just bacteria—stay alive by minimizing their sensory entropy over time, thereby helping to ensure that they remain in the statistically expected states compatible with survival.
Following the FEP, we can now say that organisms maintain themselves in the low-entropy states that ensure their continued existence by actively minimizing this measurable quantity called “free energy.” But what is free energy from the perspective of the organism? It turns out, after some mathematical juggling, that free energy is basically the same thing as sensory prediction error. When an organism is minimizing sensory prediction error, as in schemes like predictive processing and active inference, it is also minimizing this theoretically more profound quantity of free energy.
These deep connections between the FEP and predictive processing make appealing sense. Intuitively, by minimizing prediction error through active inference, living systems will naturally come to be in states they expect—or predict—themselves to be in.
the picture that emerges is of a living system actively modeling its world and its body, so that the set of states that define it as a living system keep being revisited, over and over again—from the beating of my heart every second to commiserating my birthday every year.
Let’s summarize the main steps of the FEP. In order for organisms to stay alive they need to behave so as to maintain themselves in the (low entropy) states they “expect” to be in.
What is the aspect of being you that you cling to most tightly? For many, it’s the feeling of being in control of your actions, of being the author of your thoughts.
Few topics in philosophy and neuroscience have been as consistently inflammatory as free will. What it is, whether it exists, how it happens, whether it matters—consensus
Perhaps more than any other kind of experience, experiences of volition make us feel that there is an immaterial conscious “self” pulling strings in the material world. This is how things seem. But experiences of volition do not reveal the existence of an immaterial self with causal power over physical events.
Let’s first be clear about what free will is not. Free will is not an intervention in the flow of physical events in the universe, more specifically in the brain, making things happen that wouldn’t otherwise happen.
In physics and in philosophy, determinism is the proposal that all events in the universe are completely determined by previously existing physical causes. The alternative to determinism is that chance is built into the universe from the ground up, whether through fluctuations in a quantum soup or through some other as-yet-unknown principles of physics.
Libet took advantage of a well-known phenomenon called the “readiness potential”—a small slope-like EEG signal, originating from somewhere over the motor cortex, that reliably precedes voluntary actions. Libet wanted to know whether this brain signal could be identified not only prior to a voluntary action but before the person was even aware of the intention to make the action.
The data were clear. After averaging across many trials, the readiness potential was identifiable hundreds of milliseconds before the conscious intention to move. In other words, by the time a person is aware of their intention, the readiness potential has already started ramping up.
Precisely what Libet’s observations say about free will has been debated for decades. It does seem strange that the readiness potential can be identified so long before the voluntary action. In brain time, half a second is a very long time.
There are three defining features that characterize most, if not all, experiences of volition. The first defining feature is the feeling that I am doing what I want to do.
Although making tea was fully consistent with my beliefs, values, and desires, I did not choose to have these beliefs, values, and desires. I wanted a cup of tea, but I did not choose to want a cup of tea.
As nineteenth-century philosopher Arthur Schopenhauer put it, “Man can do what he wills, but he cannot will what he wills.”
The second defining feature is the feeling that I could have done otherwise.
it certainly seemed to me that I could have made coffee instead. But I didn’t want coffee, I wanted tea, and since I can’t choose my wants, I made tea. Given the precise state of the universe at the time, which includes the state of my body and brain, all of which have prior causes, whether deterministic or not, stretching all the way back to my origin as a tea-drinking semi-Englishman and beyond, I could not have done otherwise.
The third defining feature is that voluntary actions seem to come from within rather than being imposed from somewhere else.
In engineering and mathematics, a system has degrees of freedom to the extent that it has multiple ways of responding to some state of affairs. A rock has basically no degrees of freedom, whereas a train on a single track has one degree of freedom (go backward or forward). An ant might have quite a few degrees of freedom
Following the neuroscientist Patrick Haggard, we can think of this network as implementing three processes: an early “what” process specifying which action to make, a subsequent “when” process determining the timing of the action, and a late-breaking “whether” process, which allows for its last-minute cancellation or inhibition.
Experiences of volition are useful for guiding future behavior, just as much as for guiding current behavior.
Experiences of volition flag up instances of voluntary behavior so that we can pay attention to their consequences, and adjust future behavior so as to better achieve our goals. I mentioned earlier that our sense of free will is very much about feeling we “could have done differently.”
The feeling that I could have done differently does not mean that I actually could have done differently. Rather, the phenomenology of alternative possibilities is useful because in a future similar, but not identical, situation I might indeed do differently.
the circumstances of my brain will have changed, because I’ve had an experience of volition on Monday and paid attention to its consequences. This, by itself, is enough to affect how my brain can control my many degrees of freedom when setting out to work again on Tuesday.* The usefulness of feeling “I could have done otherwise” is that, next time, you might.
And who is the “you”? The “you” in question is the assemblage of self-related prior beliefs, values, goals, memories, and perceptual best guesses that collectively make up the experience of being you.
When people talk about being “in the moment” or in a “state of flow”—when deeply immersed in an activity they have extensively practiced—the phenomenology of volition may be entirely absent. Much of the time, our voluntary actions, and our thoughts—well, they “just happen.”
An awkwardly located brain tumor can transform an engineering student into a mass school shooter, as happened in the case of Charles Whitman, the “Texas Tower Sniper,” or engender in a previously blameless teacher a rampant pedophilia—a tendency which disappeared when the tumor was removed, and returned when it grew back.
Einstein stated in a 1929 interview that because he didn’t believe in free will, he took credit for nothing.
We project causal power into our experiences of volition in just the same way that we project redness into our perceptions of surfaces.
Experiences of volition are not only real, they are indispensable to our survival. They are self-fulfilling perceptual inferences that bring about voluntary actions. Without these experiences, we would not be able to navigate the complex environments in which we humans thrive,
These days, it would be strange and almost perverse to argue that only humans are conscious. But what can we really say about how far the circle of consciousness extends, and about how different the inner universes of other animals might be?
