Where did humanity as a species come from? By the end of the 19th century scientists had accepted Darwin’s theory of evolution. So what does this mean for humanity? Nowadays humans live (almost) all over the world, but where did the first humans live? Given that we all belong to one species scientists thought that we can’t have evolved independently everywhere, but that there was an original cradle of humanity and later humans embarked on their quest to populate (almost) all continents. The first evidence for early humans was found in south-east Asia. Bias and false ideas of how early humans should have looked like led to a long period of time in which people believed humanity stems out of Asia. But in the end scientists found evidence of earlier humans in Africa. Dig into the history of humanity by listening to this week’s episode of Good in Theory.

How come predators never hunt their prey to extinction? Is this balance of species in an ecosystem a natural law or more of a superstition? Already the ancient Greeks seemed to have believed in a balance of nature and nowadays this terminology is still sometimes used. But what exactly is this balance and can it be defined in a scientific way? This question was raised in the 18th century when the discovery of fossils of unknown species radically changed our view on ecology. While some scientists still tried to make sense of it, today the world “balance” is no longer seen as useful when describing ecosystems. For a good balance of entertainment and information listen to this week’s episode of Good in Theory.

Why does your tea get cold if you leave it standing around for too long? Because the temperature of the tea adjusts to the temperature of the room, but why? The process of transferring heat puzzled many scientists. In the late 18th century caloric theory emerged in which the temperature of a body depends on the amount of “caloric” it possesses. Caloric was thought to be a weightless fluid which flows from hotter to colder bodies. The theory succeeded in explaining phenomena like your tea going cold. Although the theory managed to capture some key properties of heat it had several shortcomings and ultimately didn’t stand the test of time. If you are burning to learn more, listen to this week’s episode of Good in Theory.

How are living things created? Was there some major event of creation where all generations to come were nested inside their ancestors? Or is the creation of life a process starting when paternal and maternal fluids come together? Before the discovery of cells and atoms, some scientists believed things were infinitely divisible. This led them to the theory that even before a pregnancy there is a small human inside its parent that in turn has all possible children it will have inside itself and so on. This infinite tower of mini humans was thought to avoid the problem of how things that are not alive can create a living being. In the end this theory of preformationism in embryology found its downfall. Listen to the whole story this week on the Good in Theory podcast.

To explain why some continents that are now oceans apart seem to have once fit together, scientists hypothesized that the Earth itself must be dynamic. More precisely they thought it was expanding over time, slowly inflating like a balloon, pushing continents apart and creating oceans in between. This theory was momentarily popular but cracks soon started showing. Why was it expanding? Was it getting heavier too? Did it affect gravity? And if this was really how planets worked, why wasn’t Mars or Venus doing the same thing? Expand your minds by listening to this week’s episode of Good in Theory.

The bridge between alchemy and chemistry was crossed when scientists tried to answer the question: “Why do things burn?”. Starting from the perspective of four elements and arriving at the discovery of oxygen, this 100 year journey is a brilliant showcase of the difference between pseudoscience and science. Why do some materials burn and others don’t? How can we explain why things cease burning? To answer these questions scientists assumed that there was a material substance that left the material while burning. To learn about how this substance could help explain combustion and what hydrogen has to do with it, listen to this week’s episode of Good in Theory.

Four seasons, four elements, four directions... four humours. In ancient Greece it seemed clear that just as our world was built from four elements, our bodies must be regulated by four vital fluids. When these humours fell out of balance, disease and bad moods followed. For centuries doctors practiced medicine based on this idea: identify which fluid is winning and remove some of it until the patient stops complaining. It wasn’t until the 20th century that a discovery truly revolutionised medicine and finally laid this theory to rest. Cure your curiosity and listen to this week’s episode of Good in Theory.

How do animals adjust to changing environments? Why are some living things much more complex than others? Before Darwin came up with his theory of evolution, Jean-Baptiste Lamarck had a theory of evolution of his own. Instead of using language such as “mutation” and “natural selection”, his theory is one of gradual and intentional change. “Extinction” was also not in his vocabulary, instead he talked about “spontaneous generation” and “complexifying force”. To evolve your understanding of Lamarck's theory of evolution and how it was used culturally and politically, listen to this week’s episode of Good in Theory.