Academic kerfuffles generally don’t raise dust outside of ivy-covered halls. A rare exception involves “disruptive innovation.”

For those of you whose management bookshelf contains nothing more challenging than “Who Moved My Cheese?” the disruptive innovation concept was introduced by Harvard Business School professor Clayton Christensen in his seminal book “The Innovator’s Dilemma.” The CliffsNotes version of the CliffsNotes version goes like this: Innovation is best done by upstart businesses that don’t already have dogs in the hunt. It scares the crap out of companies that have made the serious misstep of being around for a while.

In June, the New Yorker published a tough takedown of disruptive innovation by Jill Lepore, a Christensen colleague at HBS (ouch). Lepore accuses Christensen of “hand-picking” industries and firms that have been disrupted. She argues that disruptive innovation falls short of the requirements of a strong theory: that it serve “both as a chronicle of the past (this has happened) and as a model for the future (it will keep happening).”

That criticism has unsettled executives who for years have proclaimed, “We must incubate a business within a business that puts us out of business!” What does this mean for our innovation efforts, they want to know. Is obliteration still sneaking up in our rearview mirror?

Everybody calm down. Whatever the prognosis on disruption, you will always have a reliable engine of innovation. It is called “sales.”

Yes, innovations are born within companies. But conception-;or at least fertilization-;of new ideas generally takes place outside. Most often, it is customers who provide the necessary insights and inspiration. And it is salespeople who make the whole thing possible.

In their prescient article, "The Sales Learning Curve," Mark Leslie and Charles Holloway write that the ideal salespeople are renaissance men and women able to conduct wide-ranging conversations with people in different parts of their customers’ organizations. These renaissance folks listen. They learn. And they bring their inchoate understanding back to their companies, where it is given flesh. Such a process is integral to successful innovation.

Typically, the learning curve concept is applied to new businesses. But more mature companies can take that approach as well. After all, when a customer buys a “disruptive” product from a startup, chances are it’s not because that company is a startup. Rather, its’ because no renaissance salespeople from its existing vendors were in there asking those insight- and inspiration-provoking questions. (Some companies that associate disruptive innovation with startups may prefer to buy from the new guy. If that appears true of a client, and you are not a startup, then you need to find out now.)

Startups come in with the expectation of change-;it’s the reason they exist. They win by disrupting. More mature companies can sometimes win by disrupting. But they can also win by offering wonderful incremental improvements spotted by ever-curious renaissance salespeople. Such salespeople don’t just sell a product. They sell the ability of a customer to succeed with a product. They recognize that definitions of success change over time: that people don’t eat the same way at 50 as they did at 20. With that perspective, they are at least as well positioned as startups to spot opportunities for doing something new and better.

The Renaissance was a period of invention and discovery. The best way to innovate is to hire salespeople who embody everything that the descriptor “renaissance” implies.