Mindscape Ask Me Anything, Sean Carroll | July 2026

361 | Bonnie Bassler on How Bacteria Talk and Work Together

One of the characteristics of life is that living organisms gather information and put it to use. Even one of the simplest lifeforms, bacteria, are able to sense features of their surroundings and alter their behavior accordingly. Most impressively, they are able to sense the presence of similar bacteria by a process called quorum sensing [https://en.wikipedia.org/wiki/Quorum_sensing]. Today's guest, Bonnie Bassler, is a leader in this field, and explains how quorum sensing allows groups of bacteria to do things (including in our bodies) that wouldn't be possible for individual bacteria. Blog post with transcript: https://preposterousuniverse.com/podcast/2026/07/20/361-bonnie-bassler-on-how-bacteria-talk-and-work-together/ [https://preposterousuniverse.com/podcast/2026/07/20/361-bonnie-bassler-on-how-bacteria-talk-and-work-together/] Support Mindscape on Patreon [https://www.patreon.com/seanmcarroll]. Bonnie Bassler received a Ph.D. in biochemistry from Johns Hopkins University. She is currently Andrew K. Golden University Professor of Molecular Biology at Princeton University and a Howard Hughes Medical Institute Investigator. She is a member of the National Academy of Sciences, National Academy of Medicine, and the American Academy of Arts and Sciences. Among her awards are a MacArthur Fellowship, the Gruber Prize in Genetics, and the National Medal of Science. * Lab web site [https://basslerlab.scholar.princeton.edu/] * Princeton web page [https://molbio.princeton.edu/people/bonnie-l-bassler] * Google Scholar publications [https://scholar.google.com/citations?user=d1Jk5ecAAAAJ&hl=en] * Wikipedia [https://en.wikipedia.org/wiki/Bonnie_Bassler]

Mindscape Ask Me Anything, Sean Carroll | July 2026

Welcome to the July 2026 Ask Me Anything episode of Mindscape! These monthly excursions are funded by Patreon supporters [https://www.patreon.com/seanmcarroll] (who are also the ones asking the questions). We take questions asked by Patreons, whittle them down to a more manageable number -- based primarily on whether I have anything interesting to say about them, not whether the questions themselves are good -- and sometimes group them together if they are about a similar topic. Enjoy! Blog post with transcript: https://preposterousuniverse.com/podcast/2026/07/13/ama-july-2026/ [https://preposterousuniverse.com/podcast/2026/07/13/ama-july-2026/] Support Mindscape on Patreon [https://www.patreon.com/seanmcarroll].

360 | Marc Berman on the Science of Touching Grass

Modern life has, in many ways, removed us from the environments in which our ancestors lived and adapted. Not only do we spend time looking at screens, but we spend time indoors, or outdoors but in urban spaces. How does this affect how we think and feel? Psychologist Marc Berman is a pioneer of "environmental neuroscience." In his recent book, Nature and the Mind: The Science of How Nature Improves Cognitive, Physical, and Social Well-Being [https://www.amazon.com/Nature-Mind-Improves-Cognitive-Well-Being/dp/1668058782], he presents evidence that spending time in nature not only puts us in a better mood, it makes us better thinkers. Blog post with transcript: https://www.preposterousuniverse.com/podcast/2026/07/06/360-marc-berman-on-the-science-of-touching-grass/ [https://www.preposterousuniverse.com/podcast/2026/07/06/360-marc-berman-on-the-science-of-touching-grass/] Support Mindscape on Patreon [https://www.patreon.com/seanmcarroll]. Marc Berman received his Ph.D. in psychology from the University of Michigan. He is currently Professor of Psychology and Faculty Co-Director of the Chicago Center for Computational Social Science at the University of Chicago. Among his awards is the American Psychological Association Distinguished Scientific Award for Early Career Contributions. * Environmental Neuroscience Lab [https://voices.uchicago.edu/bermanlab/] * U. Chicago web page [https://psychology.uchicago.edu/directory/marc-g-berman] * Google Scholar publications [https://scholar.google.com/citations?user=zCT_0OQAAAAJ&hl=en] * Amazon author page [https://www.amazon.com/stores/Marc-G.-Berman/author/B0FHH7CN74?ref=sr_ntt_srch_lnk_1&qid=1783334311&sr=8-1&shoppingPortalEnabled=true&ccs_id=27f214f5-70ba-4383-aa19-ffdbf690c956]

359 | Solo: Theories of Dark Energy

The cosmological constant, as discussed last episode, provides a perfectly good (thus far) explanation for why we observe the universe to be accelerating. But it might not be the right explanation, and demonstrating that would be yet another foundational discovery. In this episode I discuss what is required to invent a plausible theory of dynamical dark energy [https://en.wikipedia.org/wiki/Dark_energy], This includes considerations from particle physics, possible experimental tests, and the option that we should modify gravity rather than adding a new source of energy to the equations. Blog post with transcript: https://www.preposterousuniverse.com/podcast/2026/06/29/359-solo-theories-of-dark-energy/ [https://www.preposterousuniverse.com/podcast/2026/06/29/359-solo-theories-of-dark-energy/] Support Mindscape on Patreon [https://www.patreon.com/seanmcarroll].

358 | Solo: Vacuum Energy and the Cosmological Constant

The most surprising discovery in fundamental physics during my career as a scientist was undoubtedly the acceleration of the universe [https://en.wikipedia.org/wiki/Accelerating_expansion_of_the_universe], announced in 1998. The most straightforward explanation for these observations is a positive cosmological constant, or vacuum energy. I talk about the origin of the idea with Einstein, how quantum physicists started to think about it and understand the "cosmological constant problem," as well as how its discovery also raised the "coincidence problem." This is the first of two connected solo episodes; the next will be on theories of dark energy that are not the cosmological constant. Blog post with transcript: https://www.preposterousuniverse.com/podcast/2026/06/22/358-solo-vacuum-energy-and-the-cosmological-constant/ [https://www.preposterousuniverse.com/podcast/2026/06/22/358-solo-vacuum-energy-and-the-cosmological-constant/] Support Mindscape on Patreon [https://www.patreon.com/seanmcarroll].