I go running in the hills with a friend pretty much every weekend. Actually, I don’t run, my body does. I talk, and under the amazing druglike influence of my body’s compensation for the pain of running, I think up a lot of the stuff that goes into these essays.

My running partner and I are both at midlife, or actually we aren’t, our bodies are. But we know what that means. We’re under deadline to get done what we want to before our lives are over.

It doesn’t make us particularly anxious. We both feel on schedule, happy with how we’ve allotted our lives so far and content with our progress. We cruise along both on the running trail and in our lives, not feeling too creaky yet, enjoying the sweet spot in midlife where skills are at their peak and we’re still in good working order. We talk about our work lives and the increasingly reliable rewards that come with midlife competency, thankful to have long behind us youth’s unsure footing on unreliable terrain.

Mind Readers Dictionary: The Podfast : Play in Popup

Mind Readers Dictionary : Play in Popup

Still, there have been times over the six years we’ve run together when one or the other of us wonders out loud whether there isn’t time enough to wedge in one more magnificent caper, one more major start-up venture before it’s all over. A new business, a career change, a chance at more self-expression.

Over the hill?

The rolling hills where we run are landscaped with alluring vistas of other distant hills. They look a lot like the landscapes I sometimes use to illustrate these essays.

Landscapes with rolling hills are important in the sciences. In physics they’re used to conceptualize thermodynamics, as well as the release of potential energy as balls roll down into valleys. In evolutionary biology they’re called “fitness landscapes” and are used to model populations of organisms moved by means of natural selection toward hilltops of peak fitness. In decision theory they’re used to imagine individuals choosing at forks in the rolling roads as they seek out some optimal elevation.

The scientific use of landscapes with rolling hills is a legacy of Rene Descartes’ meditation on a housefly. Watching it flit he realized that its every position could be identified by a three-number address on a three-dimensional XYZ graph. With this insight he gave us a way to translate motion into mathematical equations. Newton employed this translation method to deliver us most of classical physics, and thence the modern world was born.

Images of landscapes are really just impressionistic math—topological equations for the rest of us. Math whizzes can look at an equation and see rolling hills. The rest of us have to look at the rolling hills themselves.

Getting to the optimal elevation: Sometimes in decision theory, we follow the physics convention and make the optimal elevation the lowest point—the groove, the pocket, a tension-free low-energy state. Sometimes we follow the convention of evolutionary biology and make the optimal elevation the high point—the peak, the pinnacle, the summit. The choice to define the high or low point as the optimal one is arbitrary; the landscape itself is just a metaphor. And actually the other two dimensions on these landscapes—the X and Z axes—are also just a metaphoric convention. Horizontal movement in any direction represents what I called “floodlighting” a few essays back, the array of all the possible moves you could make in trying to get to the optimal point.

Off the beaten path

I bring these landscapes up because they are great for depicting the midlife urge to get in one last grand ride. Imagine you’re riding through your life on a bicycle. The earlier years were rough, with unpredictable roads and a lot of uphill slogging. By now, though, you’re cruising down a gentle slope. You are reaping the rewards for having paid your dues early on in your career. There’s reliable satisfaction in your work but it’s modest satisfaction. You’re no longer amazed at your achievements—and neither is anyone else. Still, people respect you and most of the time you are content.

Out ahead you can see the end of the road. You’re not there yet but you know it’s approaching. And all around you, you see high hills, with other people on them, some just cresting, about to enjoy a thrilling ride down. You keep getting reports of brilliant, amazing, successful people, some your age or older, poised to reap the rewards of some bold adventure, in for an extended glorious glide down the hills they climbed. It makes you jealous. Indeed, it makes you wonder whether you shouldn’t exit your gentle trail, taking some side path that would take you up one more big peak in the time you’ve got left.

Fact is , it’s hard to leave the comfort of your gentle downward slope, especially to climb to a higher peak. We are creatures of habit. We’re like water following the path of least resistance or greatest encouragement. With habits and hillsides, the more you move the more you tend to move. The more immediately rewarding something is the more you tend to stick with it, unless some still more immediately rewarding alternative comes along.

Habits make it hard to change careers, so a lot of us talk about it without ever doing it. In theory we should get moving. In practice why would you want to abandon the steady paycheck, the reliable respect you’ve earned, only to reenter the white-knuckle uncertainty of a start-up venture? You’re only considering a career change because you want more downhill. Trading your descent for an ascent—that’s like Jack trading his cash cow for magic beans, but without the magic.

Unless we manufacture some magic. One way we do is through big ideas. ( see last week’s article on Ideolatry ). The other is to make the first step off your beaten path be a move on to a steeper downward slope.

“I’m going to quit my job and take a trip to Hawaii to plan my future.”

“To start my new business, I’m going to invest in a new computer.”

“I’m going to hire someone to design a label for my new record company.”

“I’m going to buy a shiny new toolkit.”

It’s tempting to begin a journey with a juicy cruise downhill, something fun. Picking fabrics for your new restaurant tablecloths, designing a fancy new Web site, remodeling your house for your new office at home. After all, how else can we get ourselves motivated to abandon today’s steady paycheck for some future uncertain glory? And virtually every new path has elements that provide this sort of early rush.

The trouble with glorious first steps like these is that what goes down must come up, if we’re ever going to get to the high peaks we’re aiming for. The Web site is done but it’s not generating any revenue yet. You’re not sure it ever will. Maybe the path you took doesn’t really lead to a peak. Maybe you should turn around and return to your old job, or maybe it’s simply that you took the wrong branch and need to find another, preferably with another glorious first step. The problem with all great ideas, however, is that they eventually degenerate into a lot of hard work.

Maybe this sounds like I’m arguing that the color of your parachute is destined to be a depressing brown. I’m not. I am counseling prudence, but mostly I’m suggesting a metaphor that represents nicely all the prudence you need. You like gliding down. You want more glide down than you’re getting, so you decide to ride up to a higher peak. The rides you’re most drawn to, however, start out as rides down. Monitor this tendency and look beyond the immediate appeal and you’re more likely to make the right move, whether it be to break away or keep your day job.