My first model organism was Physarum polycephalum. We studied how gene expression changes as cells grow and prepare to divide, and P. polycephalum is an especially good choice for this. It behaves as if it were a single giant cell, even though it is tens of centimetres across. We could take samples at different times during its growth and study how gene expression changes through the cell cycle.
There is much more one can do with P. polycephalum. It is just a slime mould, yet it is so fascinating that it has its own exhibition at the Paris Zoo. For example, it can learn how to find the most efficient path to connect to different food sources. It remembers which paths lead to rewards and which to punishment. And it does all of this without the complexity of specialized cells such as a nervous system. Does this mean that even a single cell can think, as it can solve problems and remember what works? Obviously, the answer depends on what we mean by saying “it thinks.”
Of course, this is also the question to ask about AI.
It’s easy to presuppose that an AI agent thinks and to speak of it in such language. But when we do, we are losing sight of what it truly means to think. We also lose the sense of the specifically human responsibility that thinking involves.
AI is an outstandingly efficient tool to help me navigate information. It takes advantage of the structure of knowledge. This is not the same as thinking. Inasmuch as it is part of my thinking skills, it is the part of my thinking that remembers what I read and how it fits with what else I read. But when I think, I do more than this. I choose what to focus on, what question to ask, which memory to retrieve, and which thoughts to pursue. Most importantly, I think about what is important and why it is important.
Knowing what matters makes all the difference. AI navigates the knowledge space in response to questions, and P. polycephalum finds the most efficient path to food. Just as P. polycephalum, I will reliably find my way to the refectory when there is food to be found. Just as AI, I know where to look up the answers to questions that I ask. But of course, I do not just go to the refectory because I am hungry. It’s part of our life to be together not only at prayer but also at meal times. And when I ask questions, I do not simply solve a problem that someone put before me. I ask questions because I know that it matters to know.
When we think, there is always something else beyond the practical that is difficult to pin down. It’s like we are just lifting the veil a little bit to get a tiny glimpse at the meaning of being. Philosophers speak of the transcendent good, true, and beautiful. Not just good or true or beautiful for me in this specific situation, but good, true, and beautiful in itself. Theologians say it is evidence of the imago Dei, the image of God, in the human person. Non-believers also recognize our need for meaning. When humans think about what it means to think, we recognize that there is more to it than solving problems. We get a small glimpse of what always is and what always matters, and this is a much greater accomplishment than mere problem solving.
Image credit: https://www.inaturalist.org/photos/25573047, Garrett Taylor.