In 1894, a Boston-based astronomer named Percivel Lowell found intelligent life on Mars.
Looking through a telescope from his private observatory he observed dark straight lines running across the Martian surface. He believed these lines to be evidence of canals built by an advanced but struggling alien civilization trying to tap water from the polar ice caps.
He spent years making intricate drawings of these lines, and his findings captured public imagination at the time. But you’ve never heard of him because he turned out to be dead wrong.
In the 1960s, NASA’s Mariner missions captured high-resolution images of Mars, revealing that these “canals” were nothing more than an optical illusion caused by the distribution of craters on the planet’s surface. With the low resolution available to his telescope at the time, these craters looked to Lowell like straight lines which, through a chain of reasoning, he theorized to be canals built by intelligent life.
Lowell’s story shows that there are at least two important components to thinking: reasoning and knowledge. Knowledge without reasoning is inert—you can’t do anything with it. But reasoning without knowledge can turn into compelling, confident fabrication.