Tuesday, January 26, 2016

Marvin Minsky

Marvin Minsky has passed away from us last night. Right before I got the sad news, I had spent an hour in a conversation with a friend in on the other side of the continent, discussing how Marvin has influenced our work and our way of looking at what makes us human.

(Marvin Minsky, me and Cosmo Harrigan, at his house)

Marvin Minsky was quite certainly the most influential thinker about the nature of our minds in recent history. When psychology focused on behavior because it had failed to develop methods to study mental processes, thought and intentionality, Marvin realized that minds are information processing systems, and we can make progress in understanding them by building computer models of these processes. Minsky became the founding father of this new computational science of the mind: Artificial Intelligence. 

Marvin Minsky did not think that minds are governed by a simple general principle, like neural learning, or homeostasis. The richness and depth of what makes us human requires an enormous complexity of cooperating and often self-regulating mechanisms, which Minsky started to address in his famous "Society of mind" theory. He pushed hard against approaches that he considered too simplistic, and inadvertently contributed to the schism between symbolic AI, which started out to address higher levels of cognition, and connectionist AI, which concentrated on learning, perception, and motor control.

AI has always been the pioneer battalion of computer science, but despite all its engineering successes, it is still far from explaining intelligence. We may have discovered many pieces of the puzzle, but we are still in the early stages of fitting them together.

Nothing is as strongly associated to the Massachusetts Institute of Technology as Artificial Intelligence and the person of Marvin Minsky himself. In the 60 years since Marvin started the field, he has inspired several generations of students and researchers to think about minds. Many of his inventions, and scientific contributions, his deep, yet very accessible books and his lectures were far ahead of their time, and have not lost any of their relevance.

Marvin Minsky's ideas led me, as many others, on my personal scientific quest. It has been an incredible honor to get to know him during the past year, and my thoughts are with his family and his friends.

I believe that today, the need for working on AI is as pressing as ever. Psychology is still unable to formulate and test theories, neuroscientists are entirely focused on nervous systems and not on minds. Artificial Intelligence is our best bet at understanding who we are, and it is time to continue Marvin's work, to recognize and describe the the richness of our minds, and to build machines that think, feel, perceive, learn, imagine and dream.

Monday, January 25, 2016

No, the universe is not a brain.

At Forbes, Ethan Siegel asks if the universe may be alive. This might bring us to the question what it means to be alive. When biologists started their field, they could only define it by extension (e.g. animals, plants and other similarly animated things), but did not yet have a functional definition of what made the living stuff so special, and came up with vague and wrong ideas (like a motive force, a vis vitalis, permeating living tissue). Now, a few hundred years later, biologists have agreed that they study the class of systems that are organized into one or more cells and self-organize and stabilize based on information stored in DNA. By that definition, the universe is quite certainly not alive.

However, Ethan Siegel (and a few others, like Bernardo Kastrup) suspect that the universe might be conscious, i.e. that the structure given by its stars, galaxies and galaxy clusters might lend itself to a giant information processing architecture.

Arguably, the field of cognitive science is still comparable to early biology when it comes to defining its object of study: researchers somewhat agree that higher mammals, birds and octopi have minds, cognition, a degree of intelligence and awareness, but we do not have a universally accepted functional definition of these properties. Fortunately, cognitive scientists have discarded the vis vitalis equivalent of the mind: the soul, and most of them will agree that minds are motivated information processing systems that make sense of their environment. In a biological organism, this information processing is facilitated by the exchange of signals between different types of neurons and possibly involving glia cells, by means of electrical impulses and chemicals that either act on large portions of the nervous system, or locally at the interface between individual neurons.

It is not clear what environment our universe should make sense of, but contemporary physics tells us something about the limits of its information processing.

Both Siegel and Kastrup (and Clifford Pickover, and oh well, you know who you are) like to illustrate their arguments with the following image:

This image sends a clear message: if we squint a little, then a well-chosen cutout of a false colored image of a golgi stained pyramidal neuron will look like a red down feather, and a well-chosen cutout of a differently false colored galaxy cluster also looks like a purple down feather, and therefore it is extremely likely that the universe is a giant brain.