2 Introduction

The investigation has begun. But where do we start, if we can’t even agree on what intelligence is?

It’s hard to explore a territory when we don’t yet know its boundaries.

So we decided to begin by telling you about those who, over time, tried to measure intelligence — to turn it into numbers — long before they had a full picture of the landscape they were stepping into.

We’ll tell you about the first attempts at the end of the 19th (7th) century, when people sought a way to identify “superior” human beings by intellect, just as horses were selected for strength and speed.

We’ll tell you about the mid–20th (8th) century attempt to create a test that could reveal whether a machine might be capable of thinking.

And although many of those tests now feel distant — or even absurd — here you’ll have the chance to try some of the most notable ones, from the past and the present.