The Holographic Approach to Critical Points

Scale invariance in quantum physics is usually associated with critical points which occur at specific phase transitions. There, fluctuations occur on all length scales and the system is described by a conformal field theory. In this framework, scaling dimensions and correlation functions can be computed....

Appealing to Intuitions - Why We Can't Get Along Without Them

Appeals to intuitions have something suspect about them. Intuitions can vary from person to person, and even those that seem least assailable sometimes lead us astray, as the paradoxes of set theory demonstrated. Mathematicians of the last century, in their attempts to formalize mathematics, tried to...

Free Will and the Brain: Some Current Confusions

There has been a recent explosion of writing by neuroscientists and psychologists about how "science shows us" that we don't have free will. The problem with this work is that it confuses several quite different issues. Once we sort it out, we find that there have been in fact some important discoveries...

The Most Human Human: What Artificial Intelligence Teaches Us About Being Alive

Brian Christian is the author of The Most Human Human: What Talking with Computers Teaches Us About What It Means to Be Alive. His writing has appeared in The Atlantic, Wired, The Wall Street Journal, Gizmodo, and The Guardian. Each year Turing Test sponsors confer the title of "Most Human Computer"...

Animal Social Learning and the Evolution of Culture

Both demographically and ecologically, humans are a remarkably successful species. This success is generally attributed to our capacity for culture. But how did our species’ extraordinary cultural capabilities evolve from its roots in animal social learning and tradition? In this seminar I will provide...

Revisiting Resource Scarcity, Warfare, and Violence

After a brief review of earlier cross-cultural research on warfare, I turn to more recent research focusing on eastern Africa, a region frequently plagued with subsistence uncertainty as well as violence. In that research, we explore whether resource unpredictability and chronic scarcities predict higher...

WHAT IF? Architecture, Ecology, Innovation and the Design of Cities

Cities, and over half the world’s population living in and around them, are now clearly an integral part of earth’s ecology. Arcosanti, the urban experiment founded 40 years ago by architect Paolo Soleri in the Arizona desert, would place cities at the very center of that ecology, at the very center...

A Tale of Two Averages: Towards New Socio-Economic Paradigms

This talk begins by examining how the widespread use of ensemble averages to study asset price fluctuations leads to perilous advice about how much one should borrow to invest. It is argued that time averages are more relevant in the non-ergodic processes typically found in finance and lead to the definition...

Bacterial Growth Laws: Origins and Consequences

There has been a dramatic surge in the number of physicists working on biological problems during the past 10 years. Collaboration at the physics-biology interface typically consists of physicists contributing new methods of measurement or analysis to enhance the power of biological investigations, or...

Complexity Beyond Academia: A Conversation about the Value of Complex Systems Thinking for Businesses, Non-Government Organizations, and Governments

Businesses, Non-Government Organizations (NGOs), and governments act within complex systems. They must make predictions about complex phenomena like markets, social movements, urbanization and migration, the price and availability of natural resources, and the evolution of power dynamics in industries...

Sources of Unpredictability in Viral Fitness

Virus emergence is a complex, multilevel problem that results from a combination of ecological and genetic factors. To forecast when and how new viruses may emerge we must first identify the factors determining the distribution of genetic variants within the reservoir host as well as across all potential...

Irreversibility and the Second Law of Thermodynamics at the Nanoscale

What do the laws of thermodynamics look like, when applied to microscopic systems such as optically trapped colloids, single molecules manipulated with laser tweezers, and biomolecular machines? In recent years there has been considerable interest and progress in addressing this question, and it has...

Why Did Einstein Write a (Bad) Love Poem to Spinoza?

Spinoza was a seventeenth-century über-rationalist who employed a truly bizarre methodology, attempting to prove everything — from the nature of the world, to human nature, to the ethical meaning of our lives — from first principles, in the style of Euclid. Why would a scientist take seriously anything...

Automatic Estimation of Transmitted/Founder Variants in Early HIV Infection

Little is known about the progression of HIV in the early stages after infection. Knowing the number of Transmitted/Founder variants that entered the body at the time of infection could be useful to scientists, including those who study the accuracy of animal models, the correlation of viral diversity...

The Architecture of Cyberdefense

The need to build an effective cyberdefense system offers any democracy an opportunity to make progress on a fundamental political aspiration — increasing citizen participation in public affairs. This is due to the chief military characteristics of cyberwar, namely that (a) battle incidence is massively...

Integration and Gating of Sensory Information is Achieved by a Single Cortical Circuit with Orthogonal Mixed Representations

Computations in neural circuits are inherently flexible, allowing humans and animals to respond to sensory stimuli with actions that are appropriate in a given context. Fundamental to this flexibility is the ability to integrate only context-relevant sensory information while ignoring irrelevant, distracting...

The Deep History of Human Population Size

Flavor Network and the Principles of Food Pairing

Animals, especially omnivores, feed selectively to fulfill energy needs and nutrient requirements, guided by chemical cues perceived as flavors. Among animals, humans exhibit the most diverse array of culinary practice. The diversity raises the question whether there are any general patterns of ingredient...

Social Influence and Drift in Collective Behavior

Many explanations of human behavior – even among the 'social' sciences – start with people as isolated individuals, maximizing benefits versus costs. Panics or 'herding' events are often seen as anomalous departures from this norm. I would like to suggest that humans, whose very brains have evolved...

The Microbial Search for Iron: How and Why

Microbes must struggle to acquire the essential nutrient iron from their environment, which can range from oceanic waters and soil to a mammalian host. This is further complicated by the fact that iron in the wrong place at the wrong time in a biological system is also toxic. To facilitate iron bioavailability...