The opinion that was agreed upon was that a degree in exact sciences is proof that one can absorb a lot of information in a short time and that one has common sense.
It does not prove everything but it is substantial proof that one remains stress resistant.
On top of this, some good to very good psychomotor skills need to be present and a personality profile that meets the required criteria.
All the aforementioned criteria have deteriorated mainly because the job has become easier and training has been commercialized.
ATPL has become a multiple choice with no longer any requirement of in depth knowledge. This can not be compensated during training in the Airlines and is a basic responsibility of the CAA.