Free Will?


April 2012
Ivan Obolensky

Does free will actually exist? Do we really select our own decisions? This is called the Free Will Question, and it has no easy answer.

One side argues we are in charge of our fate, and that we are responsible for our actions and decisions. To advocate any less responsibility is to undermine the existence of law and order. If we are not in charge of what we do, then why hold individuals accountable? After all, what would one say to the 1.7 million people of the United States that are either in prison, on parole, or on probation if this perception was in error?

This could be considered the strong case for free will. One did it, or one did not; once a finding of fact has been proven, then the consequence becomes a finding in law. If the law is incarceration for three years, then it is three years. Ignorance of the law is no excuse. All members of society must be held to account for their actions.

The other side argues that we are the sum of many parts, and our actions are dictated by genetics, upbringing, and the environment. We make decisions in response to situations thrust upon us. We have little control in actuality. Governments impose certain behaviors through laws. Economic booms and busts determine the ability to support oneself and one’s family. Circumstances restrict our choices to only a few possible moves. So how can we be fully responsible?

A government says it can create an economic environment that promotes growth and employment. If there is an economic disaster, who is really responsible: the worker with no job?

Randomness can also create situations in which we have no say in the outcome. A chance natural disaster can bring about circumstances that challenge even the most moral and ethical. Can these be considered extenuating circumstances?

The above might be considered a strong case for no self-determinism.

There are intermediate positions. Some consider that we may not have self-determinism, but we are still morally responsible for what we do. One might call it making the best of a bad situation. We may not be fully in control but the alternative to no law and order enforcement is far worse. We must be held responsible. Chaos is the alternative.1

And just when most positions on this issue have been defined, there comes along a growing body of biological evidence that creatures of all levels of complexity can be influenced by parasites and that parasites can dictate behavior.

Behavior-changing parasitic relationships have been in effect for millions of years. Biologists researching fossil plants of 40 million years ago found peculiar punctures in the underside of a leaf. These marks are identical to those found when a fungus, Ophiocordyceps unilateralis, infects carpenter ants. The fungus compels the infected ant to climb up a stem to the bottom of a leaf and bite into a major vein of the plant. The ant becomes paralyzed, and the fungus grows a stalk from the victim’s head to release spores which infect more ants. The 40 million year-old fossil showed twenty-nine scars that match the indentations of modern-day fungus-infected carpenter ants.2

Similarly chilling interactions have been found in fish, crabs, snails, and elsewhere in the animal kingdom. As parasitology advances, more relationships are being discovered.

Toxoplasma gondii has been in the news. It is a species of protozoa, similar to an amoeba, or a paramecium. It is estimated that half the world’s human population carries a T. Gondii infection according to the CDC. It is the most common foodborne parasite that results in hospitalization of the host and is the third most common foodborne parasitic infection. A study in the UK found that 38% of commercial meat sold in grocery stores had T. Gondii cysts.

The primary host of this parasite is the cat family. The T. Gondii life cycle has two phases. The sexual part of the cycle takes place only in cats (domestic and wild). The asexual part of the cycle takes place in any warm-blooded animal such as mammals and birds.

When T. Gondii infects rats and mice, it alters their behavior by making them irresistibly drawn to the scent of cat urine. In males, studies show that the infection seems to activate mating urges in them as if in the presence of females which overpowers their normal aversion to cats. This behavior places them in the vicinity of a cat where chances are the mouse or rat will be ingested by the cat and the protozoa is able to complete the sexual part of its life cycle.

There are indications that T. Gondii can also influence human behavior. T. Gondii infections have been linked to decreased novelty-seeking behavior, slower reactions, insecurity and neuroticism. Several studies have shown a T. Gondii role in certain cases of paranoia and schizophrenia.

There is also a correlation between prior T. Gondii infections in mothers, and the incidence of male human births, with an increase in the probability of a male birth rising to 72%. Other behavioral changes include increased attraction by males to a woman with the parasite.3

We are only now beginning to become aware of the complex dynamics between parasite and host. Parasites make up the majority of all species on Earth. There may be up to four times as many parasites as there are free-living species which means parasitic behavior is the most dominant behavior of life on this planet.4

Viruses, too, play a far larger role in our existence than once thought.

They are the most abundant life-form on Earth with a staggering 100 million different types.

There are approximately ten billion viruses in every liter of sea water. Microbial oceanography is in its infancy with the role of marine viruses only now being understood. Viral infections control the spread of marine plankton and bacteria which might otherwise choke all other life in the oceans.5

The more we learn, the more we become aware that we live suspended in a complex web of interdependencies. We like to think of ourselves as being the primary source of change on the planet only to find this influence moves in both directions. The real driver of change is the complex and ongoing relationships between parasites and hosts, and it is far larger and more powerful than previously understood. So what does that make of our free will?

1 Pink, T. (2004). Free Will: A Very Short Introduction. Oxford, U.K.: Oxford University Press.

2 Choi, C. Q. (2010, August 17). Mind-Controlling Parasites Date Back Millions of Years. Retrieved April 11, 2012, from

3 Body Horrors. (2011, April 28). Consider the Carpaccio: Looking at Toxoplasmosis. Retrieved April 12, 2012, from

4 Zimmer, C. (2000). Parasite Rex: Inside the Bizarre World of Nature’s Most Dangerous Creatures. New York, N.Y.: Free Press.

5 Crawford, D. H. (2011). Viruses: A Very Short Introduction. Oxford, U.K.: Oxford University Press.


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