Dependency theory is essentially a follow up to structuralist thinking, and shares many of its core ideas. Whereas structuralists did not consider that development would be possible at all unless a strategy of delinking and rigorous ISI was pursued, dependency thinking could allow development with external links with the developed parts of the globe. However, this kind of development is considered to be "dependent development", i.e., it does not have an internal domestic dynamic in the developing country and thus remains highly vulnerable to the economic vagaries of the world market. Dependency thinking starts from the notion that resources flow from the ‘periphery’ of poor and underdeveloped states to a ‘core’ of wealthy countries, which leads to accumulation of wealth in the rich states at the expense of the poor states. Contrary to modernization theory, dependency theory states that not all societies progress through similar stages of development. Periphery states have unique features, structures and institutions of their own and are considered weaker with regards to the world market economy, while the developed nations have never been in this colonized position in the past. Dependency theorists argue that underdeveloped countries remain economically vulnerable unless they reduce their connections to the world market.