Than van Nispen (Biology): When we think of endangered species, we often think about what they look like and how sad it is that we will never get to see them again. Some we might never even discover. We think about their place in the ecosystem and what will change when they are gone.
But there is also such a thing as the acoustic niche in which they can be found. This is the set of sound frequencies with which they communicate, which differ from species to species and even within a species, depending on their habitat. If they share a biotope with many other species, they use a smaller part of the available audio spectrum, and if circumstances require it, they seek out a very specific frequency. Think of the low tones that elephaants and whales use to communicate over long distances, or the echolocation of bats, which only works with ultrasonic sound. But also birds that sing differently in one area than in another.
This specialization takes place on an evolutionary timescale. When a species becomes extinct, a gap apppears in the soundscape, a silence that indicates that a species once lived here. How does the world sound different when they are no longer there? Will another species take its place in the sound palette of the ecosystem? Perhaps the mythical Kaalstaart? Or will the world just become a little quieter? What will be the new balance between the sounds of nature, the elements, and humans, or biophony, geophony, and anthrophony?
A search for something unknowable.

Jeroen van der Sluijs (Earth sciences): "Urgent problems like climate change and the loss of biodiversity are characterised by intamable uncertainties in scientific knowledge, difficult to overcome conflicts over values, and big interests at stake. Such issues call for post-normal, pluralistic, science that is open about uncertainties, that engages in dialogue with perspectives and types of knowledge other than natural scientific ones needed to solve such problems, and that can build bridges between all the various forms of knowledge that can contribute to solutions. How can art lure science out of its ivory tower of certainties?"

Jaap-Henk Hoepman (Informatics): Internet services tend to grow exponentially because marginal costs are almost zero. It hardly matters whether you have 100, 100,000, or 100,000,000 users. n this aspect, the virtual world differs from the traditional physical world, in which the laws of nature impose constraints. That is not always bad. Indeed, a the vurtual world could do with a little friction. That could prevent fake news from being able to spread so fast, and governments and companies from monitoring us 24/7 without significant costs. What kinds of 'friction', what laws of nature, could or should also apply in the virtual world? And how could these be enforced?

Frans Snik (Astronomy): "Chances are that in the next decades astronomers will find indirect evidence of the existence of primitive life on a planet revolving around a nearby star. These discoveries will have great significance for humanity, and therefor it is all of humanity will have to relate to them. How can scientists (not just astronomers) and artists already cooperate to shape the search for extra terrestial life? What exactly are we looking for? When are we certain enough that our telescopes are really icking up signs of life? And what will be our erthly reaction when they do?"