As a teenager, the science journalist Amanda Gefter had a “conscientious objection” to mathematics. She often slept through her high school class on meteorology – a class that, incidentally, she only took because she wanted to avoid physics – and when she went to university, she studied creative writing and philosophy rather than science. At the same time, though, Gefter was also reading pretty much every popular-physics book she could find, as part of a private quest in which she and her father sought to understand what science tells us about the nature of reality.

One of the most important figures in Gefter’s quest was the late John Wheeler, who popularized the term “black hole” and also wrote extensively about physics and philosophy. Wheeler’s ideas included the “participatory universe”, which he represented with cartoons like the one shown above. In the cartoon, an observer looks out upon the universe, but its perspective can never be totally independent because it is, itself, a part of the universe it is observing.

In this podcast, you’ll hear Gefter talking about Wheeler, the role of observers and the complex relationship between mathematics and meaning.