The classic approach to corporate strategy starts with a presumption: that with sufficient analytical rigor and an adequate assessment of the probabilities, strategists can pave a predictable path to the future from the matter of the past. In this world, they make reasonable assumptions about the evolution of product markets, capital markets, technology, and government regulation and, in effect, "assume away" most risk. Chief executive officers articulate strategy every few years, often in the context of a change in top management.

Such traditional strategy formulation often pays lip service to the perspectives of the capital markets, to changing industry structures, and to the forces at work in the environment. But in reality, a "visionary" corporate strategy is often an internally driven reflection of what the company wants the world to look like.

But suppose we no longer believe that the future is foreseeable. What if defining and achieving an enduring competitive advantage is really just a conceit that must be abandoned? What if the outstanding fact of business, as John Maynard Keynes once described it, is the "extreme precariousness of the basis of knowledge"? What if it is no longer possible to block out the "noise" of the world’s messy reality in order to rationalize a plan to achieve predetermined outcomes?

Consider another analogy. Of two runners, one is faster than the other and can be expected to win on a level track no matter how many times the race is run. But what if the race were held at night on a path strewn with rocks and fallen trees? Suppose that the slower runner practiced both in daylight and at night, while the faster one didn’t bother to see the course in advance. The runner with the superior knowledge—the greater familiarity—would probably win even if the other were intrinsically faster. If the prize money were to rise, the value of familiarity would rise as well.

Although the world is increasingly complex, confusing, and uncertain, serendipity doesn’t have to be more important than skill in the crafting and implementing of corporate strategy. Traditional deterministic approaches to strategy aren’t likely to be up to the task of helping companies negotiate these dangerous waters, but executives need not put the fate of their businesses entirely in the hands of chance. As the global environment continually changes and risk levels rise, a portfolio-of-initiatives approach holds out the opportunity for corporations to be as flexible and adaptive as the markets themselves.