Truth You Can Trust

Following up on this month’s theme of “finding the truth.”


Scientists are skeptical by nature. It is not uncommon for a scientist to challenge someone else’s assertion with, “How do you know?” The response, “I saw it with my own eyes,” is not acceptable. Anecdotal eyewitness evidence is simply not good enough. Truth, for a scientist, comes from verifiable actions or procedures that can be replicated exactly and experienced by others. It is only when such activities are shared by many that correct explanations of phenomena can be formulated.

Science arose precisely because of the limitations of human senses and perceptions. (The word, “science” means “to know.”) When people believed what they saw, heard, tasted, smelled and felt they came to conclusions about the world at large that were deeply and profoundly wrong. They believed that the earth was flat, that the sun, moon and stars revolved around the earth, and that heavier objects fell faster than lighter ones, to name a few.

It is quite entertaining, however, to learn how you can be fooled. My book How to Really Fool Yourself exploits this fun. An illusion is not experiencing reality accurately; yet experiencing something that appears and feels very real. When you are aware of a misperception, you feel strange. You can’t help smiling. Your mind tells you that your senses are deceiving you. (The word “illusion” comes from a Latin root meaning “mockery.”) There are many reasons why illusions occur. Some are caused by built-in limits of the senses. Some are based on conflicts between senses. Some are psychological and come from false expectations. And some are in the physical world itself. There is even a science that studies how we sense the world and how we interpret our sensory experiences. I drew on this science, called “psychophysics,” in creating this book and included illusions for all the senses, not just sight, which is our dominant sense. Seventy percent of all our receptor cells are for sight and when vision is in competition with another sense, vision wins. As a result there are more visual illusions than illusions for other senses, but our other senses are susceptible. Aristotle's Illusion, for example, is a touch illusion. Cross your middle finger over your index finger. Run the crossed tips of your fingers up and down over your nose and underneath near your nostrils. You will feel two noses! I have some other amazing activities in my book, but don’t take my word for it here. See for yourself.

The experiments on fooling yourself in my book show two important things: most of us perceive in similar ways and our perceptions can similarly lead us astray. Throughout the history of science, it has been extremely useful to know how we can be fooled. By knowing our weaknesses we create tools to correct them. By knowing our limitations we create tools to overcome them. The telescope and microscope clearly extend the limits of vision. Computers have memories that make no mistakes when it comes to total recall. Great minds create models of never-seen objects like atoms and molecules that can explain the events we do experience. Such concepts create another reality that helps us to understand the universe and leads to a different kind of truth, one built incrementally on the foundation of collaboration and replicable human activities. It allows us to create the magic of technology. It's a truth you can trust.