Galilean Relativity and the Invasion of Scotland

A few centuries ago, when Galileo (1564-1642) was trying to make a couple of points about how our world really works, one of the arguments that frequently came up in response to his ‘the earth orbits the sun’ theory was “if the earth is moving through space, how come I don’t notice?”

Not that I have much to begin with, but I don’t feel the wind constantly in my hair, I don’t get orbit-induced motion sickness, so why, Galileo, don’t I notice this movement as the earth is spinning around over 100,000 km per hour?

His answer is known as Galilean Relativity and it contains principles that have broad application in life.

Understanding Galilean Relativity allows you to consider your perspective in relation to results. Are you really achieving what you think you are?

First, an explanation of the theory.

Imagine you are on a ship that has reached constant velocity (meaning without a change in speed or direction). You are below decks and there are no portholes. You drop a ball from your raised hand to the floor. To you, it looks as if the ball is dropping straight down, thereby confirming gravity is at work. You are able to perceive this vertical shift as the ball changed its location by about three feet.

Now imagine you are a fish (with special x-ray vision) and you are watching this ship go past. You see the scientist inside, dropping a ball. You register the vertical change in the position of the ball. But you are also able to see a horizontal change. As the ball was pulled down by gravity it also shifted its position east by about 20 feet. The ship moved through the water and therefore so did the ball. The scientist on board, with no external point of reference, was not able to perceive this horizontal shift.

This analogy helped Galileo explain why we don’t notice the earth moving — because we’re at the same constant velocity, moving with our planet.

It can also show us the limits of our perception. And how we must be open to other perspectives if we truly want to understand the results of our actions. Despite feeling that we’ve got all the information, if we’re on the ship, the fish in the ocean has more he can share.

History offers an illuminating example of this principle at work.

In the early fourteenth century, two English kings (Edwards I and II) were repeatedly in conflict with Scotland over Scottish independence.

Nationalism wasn’t as prevalent as an identity characteristic as it is today. Lands came and went with war, marriage, and papal edicts, and the royal echelons of Europe spent a lot of time trying to acquire and hold on to land, as that is where their money ultimately came from.

There were a lot of factors that led Edward I, King of England, to decide that Scotland should be his. It has to do with how William the Conqueror divided things up in the area in 1066, the constant struggle by the English for the strategic upper hand against France, and more generally, the fact that the King of England was at the head of a feudal system that, “by enlarging a class of professional soldiers who owed military service in payment for land, it enabled it,” says William Rosen in his book The Third Horseman: Climate Change and the Great Famine of the 14th Century.

Edward I wanted to rule Scotland. The Scots weren’t interested. He invaded half a dozen times and succeeded only in giving birth to a separate Scottish identity. His desire for Scotland became his Galilean ship. He couldn’t see beyond that desire to understand how his actions were actually fundamentally undermining his goals.

History regards Edward I as a decent king. Strategic in battle, a good administrator, and so one can assume that what he generally wanted was to rule over a prosperous and powerful country. In his mind then it may have been a very simple equation – since prosperity in the middle ages was tied up with land, then to have more of it must be good. And Scotland was in a convenient location, as opposed to, say, Mongolia.

What Edward I did not see was that the repeated invasion of Scotland was undermining the very prosperity and power he was hoping to augment. It was costing tons of money, money that had to be raised from the nobility that supported his monarchy, which in turn had to be raised via the peasants from the land. People were getting sick of watching their taxes go up in flames on the Scottish border. And, as Rosen claims, “A king’s authority depends utterly on the loyalty and faith of his people.” Lose your popular support and you lose everything.

When Edward I died, his son, Edward II, inherited his father’s quest to own Scotland. He too repeatedly invaded with no lasting success. And he had it even worse. The beginning of his reign coincided with a major famine that decimated the population. This was followed by diseases that swept through the agricultural animal populations. So there was less money to support war.

But Edward II kept taxing and invading Scotland anyway, indifferent to the plight of his people. This contributed to widespread disgust with his reign and eventually led to his being disposed of, and likely murdered, in favor of his son. A cautionary tale on what happens when you lose the loyalty of the people you are meant to be leading!

This all begs the question, was Scotland really such a great prize to justify the repeated attempts to conquer it?

The answer is no. As Rosen writes, “the conquest of medieval Scotland was, by any rational economic calculus, a poor bargain for both of England’s King Edwards, who together spent more than the entire value of the country in one failed expedition after another.”

They certainly did not see this.

It is important to know that in Galilean relativity, neither the perspective of the scientist on the ship nor the fish in the ocean is incorrect. Both perspectives are true for those doing the observing. Because the scientist has no external frame of reference, he is not mistaken when he says that the ball moved only vertically, and not horizontally.

You aren’t always going to be able to adjust for Galilean relativity. Given the roles, expectations, and mythology surrounding kings, both Edwards were acting according to the viewpoint they had.

So discussing the attempted conquest of Scotland by both Kings is not about revealing that their assumptions were incorrect. From their perspective acquiring land was always a good thing. But by failing to consider other perspectives they didn’t achieve their intended results – control of Scotland – and, more importantly, were unable to appreciate the results they were affecting. More land cannot come at the expense of support for your leadership.

It is likely that at least one advisor might have said to the Edwards, ‘hey, maybe you should spend some more money on preventing the starvation of the population that pays you taxes and take a break on this Scottish thing’. This is where understanding Galilean relativity is useful – you won’t shoot the messenger.

You will know that sometimes you are on the ship, and the limitations this entails, and so be open when the fish shares his perspective with you.