It is strange to suggest that the will is not omnipresent. Especially if we are talking about living beings, it is triply strange.
But what do we call the will? Is it one common to all, or does everyone have their own?
Wikipedia says: - "the phenomenon of manifestation by a subject of his desires and intentions, capable of regulating subsequent activity and behavior, giving the ability to form more complex goals and the concentration of internal efforts to achieve them ".
Will is a vector of freedom.
Freedom is the possibility of choice.
Speaking about systems, complex systems seem to possess will. Do simple ones? There is a question about where the boundaries of the system are; in one way or another, systems interact with the outside world, but some boundaries still seem to exist. The mushroom parasite is a complex system, so it's not surprising that it has will.
Will is a very basic principle, apparently inherent in even the simplest quantum phenomena. Like the electron. Intuition tells us it is true, as do observations of living and other nature.
Why are zebras striped? We can assume that zebras are striped because all non-striped zebras died. Evolution. Will is commonly associated with intelligence and the ability to set and then achieve goals.
Well, evolution and the concept of natural selection should not be confused.
When we talk about intelligence, goal setting, and goal achievement, we usually imagine something very anthropocentric. But people are also often unaware of their own goals and plans. Conscious activity is unnecessary to exercise the will. Intelligence, on the other hand, exists in very different forms.
Intelligence is the ability to solve non-trivial problems, in general optimization problems. Consciousness is a property of human higher nervous activity. Human behavior is controlled by consciousness to a very modest extent. Most of the time a person first does something, or makes a decision, and then explains why he did so.
A human being is far from being just a brain, whose share of consciousness is measured in single percent digit.
You are not equal to your consciousness. But it is you, as a whole system, who possesses the will. At the same time, you have subsystems with their own will, which can be strongly disagree with each other. Moreover, your two brain hemispheres act and think quite independently, and only ex post facto explain each other's behavior.
An electron has one electric charge but two magnetic poles, and it can "choose" to repel or attract.
But the ability to choose does not indicate the presence of will. It is the act of making the choice that speaks to the presence of will. Or not making it. Usually the notion of choice implies the presence of some goal (direction). We usually conclude about goals by analyzing the consequences of the choice. We cannot measure will outside the act of choice either.
In my understanding, the concept of will seems to be close to the concept of Anima. One could probably try to drag thermodynamics into it, but I don't think it would be particularly useful.
I guess what's important is the fact that something happens and exists at all. And what's happening has a reason. We're observing it.
Speaking of a fungus parasite taking over an insect's brain, we can agree that what it does, it does for a purpose. It does it well. It's doing a very complex and not obvious thing, let alone that it even exists. How and why he came to it is a complicated question, but the fact that he does it is established.
We have goals, we have an opportunity, and we have the actual act of action that achieves the goal through the realization of the opportunity. Whether the mushroom realizes what it does or not is unimportant, especially since it has no consciousness by definition, because the mushroom is not a human being.
How did the mushroom come to this? Doesn't look like it did it on its own, probably as a species. There are different forms of intelligence, and different forms of intelligence manifest themselves at different levels, including in humans. Some forms of learning are only available in groups, others in societies, others only as part of an entire species.
Evolution is a strange thing.
Let's take a simple system of a hundred "synapses/neurons" Our neurons are primitive, they can be turned on or off. If you create them right, they'll produce a bunch of babies. If not, they won't.
We have total number of choices: 2^100 = 1.26 * 10^30.
Mat expectation: 0.63 * 10^30.
Let's say you create a billion samples every hour.
You would need 6.33 * 10^20 hours or 7.23 * 10^16 years to guess right.
But!
If you fix 20 neurons, and tell the rest of them to learn over a lifetime, then, the odds of finding the right combination change dramatically. With 20 neurons fixed, you only have to try a million combinations. With 32, it's only 4 billion.
That said, if we find the right combination and produce the babies, we can burn in the babies some part of the successful combination. And when we do that, the time it takes to learn will decrease.
We can hypothesize that it is the ability to learn that creates the evolutionary pressure.
Dropping down to levels below, from a chemist's point of view, the possibility of stopping, or changing a reaction by reagents will manifestation is nonsense.
But suppose the will of the reagents is to react? It seems absolutely deterministic, like two nations locked in a bloody war. Even if the individual atoms don't want to fight, it's like that chemical reaction.
Is statistical determinism an indicator of the absence or presence of will?
We can do it with people too, there is a wave function of possible reactions of a person, and its peak describes perfectly the behavior of an average person in a vacuum. And experiment with hundreds of billions of people always shows the same result, well a couple of people from a test tube sometimes go somewhere, so the wave function allows it, well he teleported through a potential barrier, it happens, nobody will catch a picoscopic person in the laboratory. And further to be sure in correctness of our quantum theory it is possible to construct a huge detector around the test tube and to detect a couple of escaped people.
There are so many things in the world that are unexplainable and unnamed, beyond anything a human can imagine. And it's beautiful.