There are those who believe that our universe is not as simple as an empty one would be and that an explanation is needed as to why our universe is as complex as it is. There is more than one issue here but firstly, just what constitutes simplicity? Here are some possibilities:
1. What is more easily learned. (But by which learning algorithm(s)?)
2. Shortest. (But in what language? Which representation?)
3. Have the greatest symmetry. (In which geometry? And which object properties are to remain unchanged by the transforms?)
4. Information-theoretic measures. (Which regularities should be counted?)
More likely what people mean by simplicity is a vector quantity again, a cluster of components. (Just like the concepts Asa H learns. For Asa most concepts are vectors.) And people won't even agree on those components.