One of them arguments was that in a vacuum, absent of any container or gravity, a liquid’s shape is that of a sphere.

Another one was that depending on the definition of liquid, liquids might or might not have a shape. This ranged from definitions of liquid based on atomic structure of molecules up to phenomenological definitions (asphalt and glass are liquids, according to some definitions e.g.). It also varies depending on the definition of the attribute shape itself.

The point of the exercise was to challenge the notion of objective truth in science.

I had a very cool class in research epistemology and the exercise was basically to answer the question, do liquids have a shape and if yes, which is it? How would you prove it?

It was the source of the most deranged but valuable discussion I’ve ever had.