Many-headed slime mold aka Physarum polycephalum, image via the French National Centre for Scientific Research, 2016
Some folks made slime think. The lowly slime mold, a single-celled protist, shows evidence of learning. It remembers the particular route that avoids irritants placed in its path by tinkering scientists. Yup. Funny thing is, the organism investigated is commonly called the “many-headed slime.” This turns out to be an ironic name, for this organism, without a central nervous system, acts like it does in fact have a head, or a brain, and maybe more than that – many heads, and many brains.
This isn’t the first time slime mold has done amazing feats. It’s used to recreate roadmaps from ancient cultures, or Tokyo’s rail system, just based on topographical information. Who do these single-celled organisms think they are, acting like they have brains? This raises the following question: Where does intelligence come from? Does it need a brain?
In Hidden Scents, while talking about the evolution of the smelling organism, I suggest that the mind is first, and then comes the body. There is something thinking in the most primitive of organisms, deciding which molecules in its surrounding sea of life, and proto-life, should be taken into it, to become part of it, and which molecules should stay outside. To be alive, one of the most basic requirements is to have a boundary between the living thing and the outside. This defines the body. But how does this body, living in a sea of potential bodyparts, determine which parts to keep, and which ones to leave behind. The body comes from somewhere, doesn’t it? And isn’t a body - a living body - more than just a bunch of molecules? If so, what’s organizing those molecules? Who is running the show?
Chemosensation is the basis of this interface, and is the process by which human olfaction works. The initial decision-making algorithms to run with this chemosensation are also the base-algorithms of human thought. Rational thought is a much more complex affair, but at the base is the limbic system, and in smelling we have a model for the kind of thinking performed by a simple, multicellular organism. Or even a collection of single celled organisms, perhaps?
Our current mode for thinking about intelligence is undergoing a major reboot. In light of developments in artificial intelligence, the boundaries of human intelligence are already blurred – many of the things once considered human, rational thought are now programmed into an "artificial life form," i.e., a computer program.
But that’s ok, because current models of the brain follow the schematics of a computer in the same way the nervous system was initially thought of as a closed network of fluids and the brain a pressure-modulator. This was in the age of hydraulics, before we knew what electricity was. Now we know what a computer is, and so the brain is like a computer. Tomorrow, we may know what life is; will we then compare the brain to it?
Our ideas on thinking and intelligence necessitate a brain (whether it’s a computer or a water pump or a lifeform). It's very counter intuitive to hear that things without brains can think. Who knows, next it will be like “Things without bodies can think.” Does the temperature in a room think? Does it have a memory?
May 2016, phys.org
Laura Sanders, Wired, via Science, 2010
Mar 2015, phys.org