Final answer:
The provided information does not answer the question regarding David Popence's view on the weakest families, but does discuss the generous welfare states of Nordic countries, Europe's shrinking family sizes, and associated economic challenges.
Step-by-step explanation:
The question regarding which country has the weakest families according to David Popence does not provide a factual answer from the provided references. The references discuss various aspects of Nordic countries such as being generous welfare states and having lower population densities compared to other European countries, but do not specifically address family strength or weakness as characterized by David Popence.
Factors mentioned related to family size in Europe include urbanization leading to smaller families, and fertility rates below replacement level in countries like Spain and Italy. Additionally, the workforce is aging and pension costs are rising due to fewer children being born, creating economic challenges for European countries.