Okaaay. So it doesn't exactly sound like the “instrument of precision” the Star claimed it to be, but coverage of Peterson's apparatus clearly highlights the era’s cultural obsession with mind-reading as the next big thing in technology. By 1910, a British psychologist claimed that thoughts vibrated enough to be discernible to those “constantly attuned” to the phenomenon. Others in academia focused on the visible form a thought might take—what colors could thoughts be? And what would those different colors mean? In 1938, The New York Times called the idea of a thought-reading machine “delightfully plausible.”

Decades of neuroscience research later, most of these mind-reading designs sound absurd. But you can’t blame people for wanting to believe. The best real-life technology begins with marvelous, outlandish ideas. Consider the technological advances that adults of the late 1800s had just lived through: Humans could now be captured on camera (1838), there were devices that could snatch sound from the air and record it (1860), people in different houses could have real-time voice conversations by talking into machines (1876), and electric lights had just been installed in the White House (1891)! The concept of recorded sound was still so new in the 1890s that it seemed reasonable—or at least the tiniest bit possible—to think recorded sound might be a precursor to recorded thought. Sounds had always been something you heard once, while they happened, and never again.

And if you haven't tried recording someone's thoughts, how do you know you can't do it? In the same way that if you haven't seen the surface of the moon, why shouldn't you be open to the idea of moon elephants roaming on it? When a new telescope was debuted in Paris in 1899, The Times (of Richmond, Virginia) called it the “telescope by which animals as large as an elephant can be plainly seen upon the moon” and promised it would “show us the large animals upon the moon and their movements.”

It was an age of mind-reading machines, and moon elephants, and horse-powered hippocycles (to be fair, the hippocycle inventor called his design, below, more theoretical than practical):

And although video calls didn't become a reality in 1912, as the Chicago Day Book predicted ...

... they did become a reality. Timeless ideas, it turns out, often just have to wait for technology to catch up with them. Impossibility is either realized or bides its time.

The promise of a mind-reading machine was, in its day, a sort of shorthand for what might be technologically possible. And a willingness to believe—or at least to explore—such an idea reflects the kind of optimism that is still essential to invention. The culture of what could be is part of how we organize all kinds of ideas about the world. It is in that same spirit today that we talk about the promises of stem cell research, gene therapies, advances in cryogenics, artificial intelligence, the search for life on other planets, &c.