Mind-altering Parasites and their Zombie Hosts

I have spent time, perhaps too much time, discussing with my girlfriend and closest friends (you don’t talk about this kind of thing with just anyone, after all) about what we would do to ensure our survival in the event of a zombie apocalypse. Ideally I would like to be holed up in Bamburgh Castle in my homeland of Northumberland only with people I completely trust, with plenty of food and weapons. Less Ideally,but more realistically, I would make for the top of my block of flats in Bethnal Green with a tent, a baseball bat and as many boxes of coco-pops I could carry and weld the door shut behind me.

This is my favourite thing about zombie movies; that they make you reflect about your own potential for survival in that situation.

My second favourite thing about zombie movies is how they make you reflect on the position of being a zombie. It may not have the heart-racing drama of feverishly welding a door shut atop a mound of high sugar cereal boxes, but it poses interesting philosophical questions. Many people are aware of the zombies/mutants thought experiment or the philosophical zombie. The philosophical zombie is a much-less-fun version of the zombies of movies; a hypothetical being in the philosophy of mind which is completely indistinguishable from humans except for one thing; they have no inner life. So you can ask a philosophical zombie (p-zombie) a question and it will give you what seems like a reasonable answer, you can punch a p-zombie and it will outwardly express that it has felt pain or you can throw a glass of water at a p-zombie and it will shout “what the hell are you doing?!” The point is despite this response, the p-zombie has had no actual conscious experience. In short, a p-zombie acts like a person but has no sentience. P-zombies are usually used for thought experiments in arguments against physicalism, however the idea of a zombie or a p-zombie may be less hypothetical than you would like to think.

In a article posted by the Guardian about a parasite named Toxoplasma gondii it was explained how this micro-organism finds a host in a warm blooded mammal, most commonly rats. However, to reproduce the parasite needs the comfort of the interior of a cat, but, of course, rats are known to avoid cats for matters of self-preservation. So how can the Toxoplasma gondii get into the cat from the rat? Well (and if you are anything like me this is already getting a bit disturbing, but it’s about to get weirder) the parasite causes the rat to start taking more risks and be less shy around cats; basically it numbs the instinctual fear the rat has of cats. This means that soon the rat will be caught, the cat will ingest some or all of the rat, and so Toxoplasma gondii is free to reproduce.

Grisly stuff. Of course this doesn’t make the rat quite like the zombie of the thought experiment, but one of the many questions brought to mind by the effect of the parasite on the rat is quite existential, especially when it is taken into consideration that an estimated 40% of the human race is already infected by Toxoplasma gondii without any noticeable effects. It is clear that if rat A is host to a parasite it will have a different ‘personality’ (if one can apply such a word to a rat) than when it was free of a parasite, namely, it will be less afraid of cats. So it could be said that this ‘personality’ trait is not inherent to rat A, it is merely like this because of the parasite. The article asserts that Toxoplasma gondii has been “implicated in the development of schizophrenia.” It doesn’t seem wise to panic over the prospect of having a bug in your brain controlling you, at least not until more research is done! But an interesting point is raised in the article itself; if you, like rat A, did have a parasite in your brain, and, again like rat A, it was adapting your personality in some way, it is clear that this personality trait is not your own but something the parasite is impressing on you. That is disturbing in itself, but what is more disturbing is to consider that if this altered trait could be identified and it turned out that the parasite was responsible for your, for example, love of a partner, would you want it removed knowing that the love was not really yours?

Interesting stuff,but essentially just pop moral philosophy. I won’t be having any existential crisis’ myself until more medical trials have been done…

Related Articles

Problems of Other Minds: Solutions and Dissolutions in Analytic and Continental Philosophy – Jack Reynolds

Metacognition – Joelle Proust


Author: Steven Hedley

I am a postgraduate student in philosophy at Kings College London and an aspiring academic.

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