Your eyes are actually an outgrowth of your brain and they're exposed right out in front. The eyes have their own extra defenses though.

Still, we have highly-effective sensors in other parts of our bodies, further away from the brain, and surely we could drop that check somewhere else. At least when it comes to eyes, one can make the argument that they should enable split-second reactions to run from that predator as soon as you spot it, so they should be as close as possible to the mainframe... whereas nobody is going to die if they can only smell wolf poo a second later.

I'm still alive today because I can detect smoke very early. This ability has saved me from indoor electrical fires and wildfires. Hunter gatherers who lived in makeshift shelters probably depended even more frequently on this ability.

If you're really worried about defending your brain from all comers, you should really start by having all your maxillary teeth pulled and replacing them with a denture plate. Their roots are a lot closer to your brain than you likely realize, and an untreated maxillary abscess is much more likely to quickly progress to fatal encephalopathy than you are to ever insufflate water containing N. fowleri.

Not the brain, just nose and mouth. Saying bye to colds, headaches, allergies, respiratory infections, with a simple filter? Fuck yes :)

> you should really start by having all your maxillary teeth pulled

Oh yeah, if I weren't so poor I would have done that years ago. I still hope to be wealthy enough, one day, that I'll be able to replace all my teeth with artificial ones that don't decay.

So, a mask with extra steps?

That, and you can be choked to death while eating always reminds me it's more a cruel joke than an intelligent design.

Market it as a COVID-19 solution, and you won't have any issues finding funding :-)