In my closest scientific surrounding, The Limits to Growth is surprisingly unknown, so at its 50th anniversary, this blog post is an intro + my reflections. For short, it’s a fascinating story of what happens when computational social science makes a splash. If we interpret computational social science literally—not just meaning social media data mining—its […]
Category: History
What complexity science is, and why
I also posted this post on arXiv, in a more reader-friendly layout and somewhat shaped-up writing. This is a post/essay about understanding complexity science, via some peculiarities of the field, as a meeting place for a special kind of scientist. It is the result of my nostalgia-driven hobby of reading popular-science complex systems books, and […]
Using networks to design an Indian village
Notes on the Synthesis of Form by maverick architect/mathematician Christopher Alexander belongs to the canon of design theory. In 150 pages of youthful enthusiasm, Alexander brings together D’Arcy Thompson, cosmology, modernist architecture, anthropology, and his own algorithm to hierarchically decompose a graph. In 1962, two years before the publication of Notes on the Synthesis of Form, […]
Faraway, so close! Nobel prize to complex systems
Yesterday, it was announced that Syukuro Manabe, Klaus Hasselmann, and Giorgio Parisi get to share the 2021 Nobel prize in physics. Woo hoo! I had a smile on my lips running through the night streets of Tokyo (my usual exercise). The best part is the motivation: “For groundbreaking contributions to our understanding of complex physical […]
Universality: Stronger than logic
I was re-reading some old universality papers. You know, universality in the stat-mech sense—the critical exponents that characterize phase transitions are insensitive to details of your model or crystal structure of your material. This insight, allegedly flowing around in the stat-mech community in the 1960s, was first articulated by Robert Griffiths in 1970. It got […]
Minds, Machines and Herbert Simon
Our designed reality Two years late to the party, I discovered the brilliant review paper “Machine Behavior” by Iyad Rahwan and an all-star cast. Its premise is that we need to let systems relying on artificial intelligence be scientific study objects in their own right, even though they are, to some extent, engineered. The article […]
{complex [systems} theory]
(This is a light-hearted and ill-researched post. When the infinite amount of free time I ordered on Amazon finally arrives, I might dig into it deeply and be serious.) Everyone who tries to read widely about systemsy stuff will inevitably feel puzzled by the large-scale flow of ideas. In particular, there is a—sometimes crystal clear, […]
Do you believe in ghosts?
I do. In the sense of phantom traffic jams—traffic jams without a bottleneck, that just emerge spontaneously (and with peculiar density characteristics—more below). The most fundamental feature of highway traffic is the “inverse-λ shape” flow-density diagram. Flow is the number of vehicles that pass a point along the road. Density is how many cars there […]
Firsts in network science
I revised this post after comments from Urska Demsar, Travis Gibson, Des Higham, Carl Nordlund, Mason Porter, Max Schich, Jan Peter Schäfermeyer, Johan Ugander, Balazs Vedres, and Jean-Gabriel Young. Thanks! Our field is interdisciplinary, and many smart people have been thinking about similar things. No wonder things get reinvented and rediscovered many times. I don’t […]
Getting down to the brass tacks (of SIR on temporal networks)
Now I turned this blog post into an arXiv preprint: https://arxiv.org/abs/2007.14386 Here, I will discuss some technical issues of compartmental models in general, and the SIR model in particular, on temporal networks. These are things that feel a bit too off-topic to even bother readers of papers, but everyone into network epidemiology needs to consider […]
Petter Holme 