"The human senses are tools of science in studying the natural world. If you can see it, hear it, feel, taste, or smell it, then science can’t work with it. This isn’t meant superficially, for scientists have developed a great variety of instruments that extend the capabilities of science far beyond the unaided senses. But even with the most subtle of instruments, the link between instrument and scientist is in the form of a meter needle whose location is seen, a photographic record or computer tape that can be read, or an audible signal that can be heard."