The next time you face a new challenge, don’t just ask yourself, “What can I learn from this?” Ask yourself, “What do I need to unlearn?”

In his #1 Bestseller Good to Great, Jim Collins talks about having not just a “To Do” list, but also a “Stop Doing” list. The logic is pretty obvious. When we’re already busy (and who isn’t?) it’s not possible to keep adding new things to do without shedding some of the things we’re currently doing. Collins argues that we should be more deliberate about stopping those activities that are not the best use of our time and resources, rather than just letting things fall away by default.

This is easier said than done. Psychologists and coaches have long understood that when it comes to changing our behavior, most of us find it easier to add rather than subtract. Deciding to “eat more healthy food” is more likely to succeed than “eating less junk food”. We don’t let go of our habits easily.

The same is all-too-true of those things we have chosen to believe. We tend to see our personal knowledge as an accumulation of information that we add to over time. We rarely reverse that process—or see any need to. Once we have concluded that we have found the “truth”, we’re reluctant to question ourselves. That would mean facing the possibility that we have been wrong. So we resist, sometimes intensely.

Such an attitude is of course not very helpful when innovation is our objective. It’s also a perception that doesn’t reflect the true nature of knowledge. Despite the approach we’ve been immersed in all our lives, in school and at work, learning is not a cumulative process. Real learning requires constant reexamination and revision. It’s a process of not just acquiring information, but one of letting go of information that may have once been true (or at least useful) but isn’t anymore. I can’t remember when I first learned that the world was round. But I can say with confidence that whenever it happened, I wasn’t just adding to my knowledge about the world; I was rejecting my previous conclusion—based on personal observation—that it was flat.

Most of us have a hard time with this “letting go” part of learning. It requires considerable courage, humility, openness and mental flexibility. Our long ingrained attitudes about the nature of what we know are hard to overcome but when we do, we gain fresh understanding. In the original draft of this article, I wrote that such letting go, “…enables us to blow right by our peers and competitors who still cling to the previous paradigm,” but that’s misleading. Because when we realize that knowledge is not cumulative, suddenly no one is “ahead” or “behind” anyone else. We’re all simply pursuing insights and a good one can trump years of acquired knowledge.

Treating knowledge as something we accumulate can really slow things down. It leads us to dig in and defend our position rather than genuinely consider new possibilities. It’s unlearning that creates breakthroughs, by loosening the intellectual log jams that so often entangle us. Are you a skilled unlearner? Do you know how to bring everyone’s unexamined assumptions to the surface, so your team can have more productive and innovative discussions that get to the real heart of your challenges?

Learning new things is commendable but it’s the unlearning that’s most powerful.