The answers given by many Eurosceptics to the challenges we face, including migration, is that we must seek our national self-interest and give up on cooperation. Eurosceptics believe that the European Union's vision is unrealistic and unachievable, because everyone works for their own personal gain. Up to a certain point, Eurosceptics are correct when they say it is wishful thinking to consider the European Union a benevolent entity that will solve all our problems. Upon closer examination, one finds that the Union is like any other human institution or state composed of various competing interest groups.

Believers in the European Union, on the other hand, say that membership of the Union guarantees self-interest. Eurosceptics argue that these people are just selfish. Whichever way you look at it, the element of self-interest is part of human nature. What is good for some may be bad for others. However, we must keep trying to align our self-interest with the success of our neighbours, so that everybody wins. Self-interest does not imply selfishness.

Eurosceptics use the concept of self-interest to argue that the European Union cannot succeed due to the irreconcilable differences perceived to exist between the countless lobbies, nations, parties, cultures and interest groups playing the game. My answer to that is that the European Union would have been unimaginable in its current form two generations ago. While others dreamed of a united Europe, its success depended on context and history. What has changed?

I argue that what has changed is our capacity for cooperation. World trade is a perfect example of how physical conflict has become much more difficult because nations now depend on one another for economic reasons. Our context, across the globe, has been until recently a process of globalisation, bringing everybody closer together through technology, economics and increasing freedom of movement. Coupled with popular culture, common language and shared values, humanity's capacity for cooperation has increased dramatically in recent history.

We now have the capacity to cooperate in a European Union, as we know it today, which was not possible two centuries ago. As history progresses, humanity's capacity to cooperate has increased. It should keep increasing, and that should be the goal and vision of progress. Civilisation is built by the coming together of groups promoting their own self-interest, creating something larger than themselves.

I warn that Eurosceptics are falling into the trap of the prisoner's dilemma. The prisoner's dilemma is a thought experiment in which two people are given the chance to either cooperate or betray one another. There are four possible outcomes, and both players who cooperate is the most profitable and most desirable outcome in this game.

However, in the prisoner's dilemma, the simplest and safest "rational" option seems to be for the players to always betray one another. Mutual betrayal is the inevitable result of the thought experiment. If you trust the other player blindly and he betrays you, you will suffer the worst outcome while he profits. Therefore, it is not worth taking the risk of cooperating. People play it safe and usually choose to betray one another in the game, and both suffer instead.

The prisoner's dilemma has taught us the importance of trust and cooperation, and warned us of the obstacles that lie in our path. There are no easy answers to our growing challenges, but my argument is that we must never forget that our true self-interest lies in cooperation, rather than betrayal. We must keep increasing our capacity to cooperate. As this capacity increases, so too our opportunities to find solutions to our problems. If we aim to align our self-interest with the health and success of our neighbours, and if they truly do the same, then that is cooperation, and everyone will, ultimately, be much better off.

Timothy Alden is deputy leader of Partit Demokratiku