When discussing human evolution and adaptation, scientists tend to make a big deal of several things. They talk about our opposable thumbs which let us use tools. They talk about our big brains with their well developed prefrontal cortexes, which allow us to imagine things and create new tools to use. Some even talk about our excellent cooling system which allows us to run long distances and our socially tuned brain chemistry which allow us to work together. All these things are great, and all of them were probably instrumental to our rise as Earth’s dominant species. However, at least one critical, relatively exceptional trait is being overlooked. What I’ve never heard anyone mention, is how important our life expectancy is.
Think about it for a second. Humans live much longer than most mammals, or most of any type of animal for that matter. Take dogs, for example. Your dog really isn’t that different from you as an organism (relatively speaking at least). We’re both warm-blooded, vertebrate, social, placental and feed our young with milk. But even with the best of care and a strict, scientifically engineered diet and plenty of exercise, dogs will usually live only about 10-12 years (maybe a little longer with smaller breeds). And that’s pretty typical for mammals. In fact, some of closest genetic relatives, after primates and prosimians, are lagomorphs (rabbits and similar creatures) and rodents, most of which usually only live a couple years. And even most monkeys only live in the 15-45 year range. Only our very close cousins like chimps and a handful of other mammals like elephants have life spans that even come close to ours.
So why is that so important? Well, think about how impossible it would have been for our civilization to rise as it has if we lived comparable lifetimes to dogs. Assume everything about who we are as a species is exactly the same as it is now. We have beautiful, useful opposable thumbs for tools. We have big, fat monkey brains for thinking up new tools and good brain chemistry for creating useful social structures to facilitate group projects. But then imagine that we only have 10% of the lifespan we do now. The average life expectancy would be eight years with people going over 10 years being something of a rarity. Like I said before, this wouldn’t be at all unusual for a mammalian species. But how drastically would this affect our ability to create a civilization? How hard would it be to come up with a theory of relativity by the age of eight years? It’s hard enough to come up with such a thing in 40 or 50 years. Sure, if we were that short lived we would probably have accelerated development, coming to adulthood at a much faster rate. But even if that were true, you still have to learn before you can do. And learning takes time. Lots of it. Even the greatest geniuses of all were not creating their most famous works by that age.
Of course, nobody comes up with new technologies entirely by themselves. They have to rely on thousands of prior discoveries that paved the way for the latest one. Each unit of discovery can be added one block at a time to arrive at our current state of technology. But there must be a minimum size of such a “discovery unit” for the system to function at all. Isaac Newton couldn’t have just written the title page of Principia Mathematica and then passed it on to the next guy.
Now here’s the part of all this that really gets me: what discoveries are we unable to make because our life expectancies are too short? What things could we discover only with a life span 10 times its current length? Maybe (and I would say probably) the Universe is so complex in some respects that minds like ours could only unravel the minimally sized discovery unit for certain secrets after 700 years of experience and work. Maybe the minimum discovery for some fields is so large that we could never achieve it. Maybe it takes so long to understand that even if everything we needed to know about the subject were written in a book given to us by a species of hyper-intelligent aliens, the knowledge would be so vast and complicated that simply learning it would be beyond our lifespan, even if not strictly beyond our comprehension.
This all leads to the question: what will happen if we do learn how to dramatically increase our lifespans? Will it open the flood gates for all kinds of discoveries like these? And I’m not even talking entirely about scientific discoveries here. How much would it change our philosophies of life, our understanding of our place in the Universe, our religious beliefs, if we could live to, say, 1,000 years old? Imagine how it would affect our psychology if the threat and fear of death were that much less impending, and if we had the experience to have seen human behavior so many times as to notice all the patterns most people cannot in the first 100 years. Imagine if we could stay in school until 50? Imagine if we had time to take on 20 different careers? Imagine if we had time to learn dozens of languages and travel to every major city on Earth many times over? There must be a wisdom that comes with levels of experience and boredom beyond our current capabilities. I for one am looking forward to such a future.