Plato, searching for a succinct definition, once deemed man the only "featherless biped." On hearing this, Diogenes promptly presented his fellow philosopher with a plucked chicken.
It's funny to picture the great thinker being the butt of such a joke, but the problem he was trying to solve -- how to separate man from the animals -- is a tough one. Long before, and ever after, people have been trying to draw that line. Animals are like this. Man is like that. Unfortunately, every line in the sand, whether built on precepts of physical differences or mental distinction, only becomes more smudged over time.
One of the guidelines that served for a long period was man's use of tools. Man was "the tool-using animal," and this distinction was even used to help separate paleontological sites belonging to "human ancestors" from those belonging to other offshoots of the hominid line. In 2001: A Space Odyssey, the critical moment that pushes man down the road to being man, is the point there the human-to-be lifts a length of warthog bone and discovers its capabilities as a club.
However, a pair of recent articles point up the folly of making tool use the test of humanity. It appears that chimpanzees had their own "stone age." Around the same time the pyramids were being constructed in Egypt, Chimps in West Africa were using stone tools to get at hard-shelled nuts. It's not only chimpanzees of the past who use tools. It's long been known that some bands of modern chimps use sticks to tease insects from their hives. Now it seems that chimpanzee tool use can be just as violent as those of our direct ancestors.
Chimpanzees living in the West African savannah have been observed fashioning spears from sticks and using the handcrafted tools to hunt small mammals -- the first routine production of deadly weapons ever seen in nonhuman animals.
Tool use in primates isn't limited to humans and chimps. Many other great apes, particularly orangutans, have been seen making use of tools. All of this suggests that tool use is something inherited from a common ancestor, not something that developed in humans alone.
So how can you draw the line between us and them? Emotions? Language? The answer is that you can't. There are no lines. Deeply unsatisfying as it is to the desire to group items into black and white (a tendency also not limited to humans), all the answers of science are grey.
Your species is not that special. Reading the text of paleontology and history, there is no bold message of certainty. Winding back the clock reveals no inexorable march in our direction, or even the triumph of "better" over "worse." Let the clock come forward again, and we would not be here -- not in a million, million tries. Likewise, human history has been defined as much by fortuitous placement of natural resources as it has been by human action. You're the tail end of the tail end of a process that much more closely resembles random chance than progress toward an objective.
Your world is not that special. Your planet is not located at the center of the universe. Neither is your star, or your galaxy. Perhaps most disturbing at all, as telescopes have revealed to us the enormity of space, both astronomy and geology have revealed the breathless expanse of time. We are not just insignificantly small items living in a vast ocean of space; we're living in a moment so brief that it's barely a single tick of a clock that's already run through millennia without us, and will not pause when we are gone.
No, you are not that special. And yet, you are a wonder, absolutely unique and irreplaceable. Your species is a wonder, gifted with physical and mental resources that provide boundless opportunity. Your planet is a wonder, swarming with life in infinite variety and complexity. Your universe is a wonder, based on laws so precisely balanced that the slightest variation in any of them might have caused everything -- space, time, and everything that moves through both -- to never have appeared.
Einstein made some of his greatest discoveries starting with pure thought experiments. Here's one you can try. The next time you are caught in traffic, look at the lines of cars around you. Instead of picturing them as an obstacles to your own progress, picture the occupants of each vehicle as unique individuals, as much at the center of their universe as you are of yours. Don't worry for the moment about trying to extend this belief to all the people around the globe, just look at the line of taillights ahead, and picture each with family, friends, and dreams. They are no less complete individuals -- and no more -- than you. This is a concept almost as difficult to hold as the scope of the universe revealed through science.
Our instinct is always toward tribalism, toward drawing lines between human and animal, manmade and natural, us and them. However, these lines don't exist outside our own minds. You can't draw a line between humans and animals because humans are animals, not less than the smallest ant or the largest whale.
But what if you start to erase those lines? Or what if you can sketch that line other people, so that you don't chase down every personal desire without considering how it affects others? What if you sketch that line to the whole planet, so that you act in ways that help not just yourself, but your fellow humans (and fellow non-humans)? Do that, and you're making real progress. In fact, some might even call you progressive.
And in my book, that makes you pretty darn special.