Our eyes are special detectors. They allow us to register information not only from across the room but from across the universe. Without vision, the science of astronomy would never have been born and our capacity to measure our place in the universe would have been hopelessly stunted. Think of bats. Whatever bat secrets gets passed from one generation to the next, you can bet that none of them are based on the appearance of the night sky.
When thought of as an ensemble of experimental tools, our collective senses enjoy an astonishing acuity and range of sensitivity. Our ears can register the thunderous launch of the space shuttle, yet they can also hear a mosquito buzzing a foot away from our head. Our sense of touch allows us to feel the magnitude of a bowling ball dropped on our big toe, just as we can tell when a one-milligram bug crawls along our arm. Some people enjoy munching on habanero peppers while sensitive tongues can identify the presence of food flavors on the level of parts per million. And our eyes can register the bright sandy terrain on a sunny beach, yet these same eyes have no trouble spotting a lone match, freshly lit, hundreds of feet across a darkened auditorium.
Before we get carried away in praise of ourselves, note that what we gain in breadth, we lose in precision because we register the world’s stimuli in logarithmic rather than linear increments. For example, if you increase the energy of a sound’s volume by a factor of ten, your ears will judge this change to be rather small. Increase it by a factor of two and you will barely take notice. The same holds for our capacity to measure light. If you have ever viewed a total solar eclipse you may have noticed that the Sun’s disk must be at least ninety percent covered by the Moon before anybody comments that the sky has darkened. The stellar magnitude scale of brightness, the well-known acoustic decibel scale, and the seismic scale for earthquake severity are each logarithmic in part because of our biological propensity to see, hear, and feel the world that way.
What, if anything, lies beyond our senses? Does there exist a way of knowing that which transcends our biological interfaces with the environment?
Consider that the human machine, while good at decoding the basics of our immediate environment—like when it’s day or night or when a creature is about to eat you—has very little talent for decoding how the rest of nature works without the tools of science. If we want to know what’s out there then we require detectors other than the ones we are born with. In nearly every case, the job of a scientific apparatus is to transcend the breadth and depth of our senses.
Some people boast of having a sixth sense, where they profess to know or see things that others cannot. Fortunetellers, mind readers, and mystics are at the top of this list of those who lay claim to mysterious powers. In so doing, they instill widespread fascination in others, especially book publishers and television producers. The questionable field of parapsychology is founded on the expectation that at least some people actually harbor this talent. To me, the biggest mystery of them all is why so many fortune-telling psychics chose to work the phones on TV hotlines instead of becoming insanely wealthy trading futures contracts on Wall Street. Quite independent of this profound mystery, the persistent failures of controlled, double blind experiments to support the claims of parapsychology suggest that what’s going on is non-sense rather than sixth-sense.
On the other hand, modern science wields dozens of senses. And scientists do not claim these to be the expression of special powers, just special hardware. In the end, of course, the hardware converts the information gleaned from these extra senses into simple tables, charts, diagrams, or images that our inborn senses can interpret. In the original Star Trek sci-fi series, the crew that beamed down from their starship to the uncharted planet always brought with them a tricorder, which was a hand-held device that could analyze anything they encountered, living or inanimate, for its basic properties. As you waved the tricorder over the object-in-question it made an audible spacey sound that was interpreted by the user.