It’s not just technology that has improved people’s lives; moral change has done so, too. In 1700, women were unable to attend university, and the feminist movement did not exist.If that well-off Brit was gay, he could not love openly; sodomy was punishable by death. In the late 1700s, three in four people globally were the victims of some form of forced labour; now less than 1 percent are. In 1700, no one lived in a democracy. Now over half the world does.

Often, some event can have highly significant, persistent, and contingent effects if there is a period of plasticity, where ideas or events or institutions can take one of many forms, followed by a period of rigidity or ossification. The dynamic is like that of glassblowing: In one period, the glass is still molten and malleable; it can be blown into one of many shapes. After it cools, it becomes rigid, and further change is impossible without remelting.

The abolition of slavery was an example of a values change, by which I mean a change in the moral attitudes of a society, or in how those attitudes are implemented and enforced. In my view, the abolition of slavery was one of the most important values changes in all of history. Over the course of this chapter and the next, I’ll argue that changing society’s values is particularly important from a longtermist perspective. This chapter will look at the significance and contingency of values changes; the next chapter will discuss their persistence.

Slavery is so abhorrent that, before getting to grips with the historical scholarship on the topic, I assumed that abolition must have been inevitable. But now I’m not at all sure. Though it’s impossible to know for certain, it’s entirely plausible to me that, were the tape of history rerun a hundred times with slightly different starting conditions, in a significant proportion of those reruns, there would still be legal slavery in many or most countries in the world, even at today’s level of technological development.

SUB-CAPABILITY NO.3: CREDIBILITY EQUITY

Sherman and Franklin made a huge impact late in life partly by drawing upon storehouses of credibility they’d built over decades. It wasn’t just Franklin’s words at the end of the Constitutional Convention that held sway, but also that these words came from Franklin. It wasn’t just that Sherman articulated a strong argument to preserve the actual text of the Constitution and use the amendment mechanism to include the Bill of Rights, but also that the argument came from Sherman.