Obama's rallying cry "Yes We Can" reached out to the American belief in belief itself. If the fact that an African American with no political dynasty can overcome significant disadvantage to provide the change that the grassroots wanted desperately doesn't appeal to belief over rationality, I don't know what does. However, it is true that the political effort to get him into the White House was an exercise of military precision too.

After two decades of workin with start-ups though, I know that those of us who go back for more punishment in the high-risk arena are those who are hard-wired to be believers. The financial value of any start-up is virtually nil. Some though can see the white space between what is and what could be. That's the strategic value, and that's why high-growth private companies sometimes are acquired for a huge multiple. The have a disruptive effect on an industry. Once a Skype is sold for $2.5bn, everyone believes. Very few believe at the beginning however.

Sir Winston Churchill is being feted this week for his imagination and resolution in the face of overwhelming odds that Nazi Germany would steamroll its way through Europe. Churchill believed things that any rational person wouldn't have believed but, but his belief in belief was responsible for saving Western Civilisation and the pride of this great country.

In my own small way, I led an expansion in the number of international entrepreneurs. FirstTuesday spread across Europe into 17 then eventually 45 cities 10 years ago yesterday. First Tuesday connected 500,000 aspiring Internet entrepreneurs with capital, talent and customers.

Roberto de Saint Malo, a First Tuesday Madrid City Leader, wrote this recently: "If I had to specify what 'touched me most' about the First Tuesday experience, it would be the widespread sense that the traditional rules could be re-visited and re-written. To be reminded that the World is not 'as it is', but rather 'as we make it'."

As we reflect on where each one of us is in our lives on the 70th anniversary of the start of the Second World War, we can also know rationally that history is written by the winners, and the winners 'believe', they don't just 'know' things.

Winners are believers in a world that they imagine, resolve to make and have faith in against all the odds.

Julie Meyer is chief executive of Ariadne Capital.