The best leaders balance their grand ambitious vision with caution and an attention to details.

The legendary Oxford professor and president of Wolfson College, Isaiah Berlin, once categorized writers by saying that “the fox knows many things, but the hedgehog knows one big thing.”

Berlin was comparing two types of writer: hedgehogs, who were people with a worldview consisting of one central idea around which everything else is related, and foxes, who paid attention to the small details and saw the world as a complex place with a variety of different, even contradictory, aspects.

Plato and Dostoevsky, for example, with their devotion to a single guiding philosophy in life, are hedgehogs, while Shakespeare and Joyce, who saw life as being far from black and white, were foxes.

Berlin’s analogy was quickly expanded upon by others to include famous leaders of our time. This time, the hedgehog represented a highly-driven and single-minded leader, while the fox represented someone who’s cautious and sees all the obstacles in their way.

With this analogy, it became apparent that the best leaders had a healthy mixture of both fox and hedgehog characteristics. Those leaders at the extreme ends of the spectrum were either too cautious or they failed to see the big picture.

Consider the story of two leaders with two different dispositions: King Xerxes of Persia, who was a hedgehog, and his advisor Artabanus, a fox.

In 480 BC, these two were considering a possible invasion of Greece. Being a fox, Artabanus was cautious and saw many potential pitfalls ahead. So he advised against the invasion and tried to warn Xerxes that the journey was too long and that they’d surely run out of food and be too exhausted to fight the mighty Greek soldiers.

Being a hedgehog, Xerxes was single-minded and bold in his decision-making. In his opinion, nothing risked meant nothing gained, so he ignored Artabanus’s worries and invaded. Artabanus proved to be right, as the Persians were too exhausted by the time they reached the Greek army.

Artabanus may have been correct on this occasion, but a leader should be wary of his approach. There are times when a leader needs to make bold decisions, and when leaders are always like Artabanus they may never make a move.

So, the ideal leader is part hedgehog and part fox – they can assess all the different angles while still being able to take determined action.

Abraham Lincoln was one such leader. He was determined to get the 13th Amendment passed in order to abolish slavery and, like a fox, he pursued a variety of angles to achieve this goal – including bribery, flattery and lies.