The four freedoms in the EU: are they inseparable?

The four freedoms regulate the free movement of goods, capital, services, and labour within the European Union. They constitute a fundamental part of the single market and the euro, and are considered one of the biggest accomplishments of the European unification project by many citizens. Brexit has added new fuel to the debate on free movement of persons. Technically, the four freedoms could be separated but what that be a useful political option?  

Dr. Anna auf dem Brinke works for the German Ministry of economy, she formally worked for the Jacques Delors Centre.