Living in the Twin Cities, here in Minnesota, I’ve had the pleasure of getting to know Art Fry, the now retired 3M Corporate Scientist who invented Post It Notes. I recently interviewed this noted innovator about how he approaches problems and ideas. One of the things he emphasized was the importance of sticking with problems long enough to solve them, not giving up on ideas too quickly. So I asked him, “How do you tell the difference between being persistent and being stubborn?”

His answer was a little mischievous but like the man saying it, it also contained great wisdom. With a slight grin, he answered, “By whether or not you’re successful.” He knew that wasn’t exactly what I was asking and we both laughed, but he wasn’t far off the mark either.

It’s easy for anyone to look back on an idea that has either succeeded or failed and draw conclusions about whether or not it was a good idea to pursue. The harder question is of course, “How does one know before an idea has succeeded or failed whether or not it’s worth pursuing?” It’s a question that I think pinpoints one of the central challenges of innovation. The hard part is not how to come up with ideas as much as how to reliably evaluate the ideas we come up with.

I like Art’s answer for several reasons. For one, it’s pragmatic. The question, “Does it work?” (Or, “Will it work?”) is a simple straightforward inquiry that should be made about any innovation. It strips away politics and ideology and habit and organizational inertia and gets to the real issue: whether the idea, when applied in the real world, will enable us to achieve some desired outcome.

Art’s answer also points to a larger truth: There’s no definitive way to determine whether an idea will succeed or fail until you try it. That’s not to say that all ideas should be tried. Some are utterly impractical, or irrelevant to the task, or too risky, or require too much effort compared to the potential payoff. There are many sound reasons for choosing not to pursue an idea but firmly concluding that it won’t work before you’ve tried it is not one of them. And that assumption (some would call it arrogance) that it’s possible to know what can’t be done when it hasn’t been attempted is what kills many promising ideas too quickly.

Another reason I like Art’s response is it says something about the attitude with which we hold onto our ideas. Just as it’s inappropriate to conclude that an idea won’t work without ever trying it, it’s inappropriate to insist it will work, if we’re not willing to test it. We need to be careful that our objective is to discover solutions, not prove that we’re right. To be persistent without becoming stubborn, we must be willing to put our ideas up against harsh realities and genuinely evaluate them based on objective data and definable results. If we’re not willing to do that in ways that expose our ideas to failure, then we’re not really experimenting or exploring, we’re just trying to confirm our beliefs.

There’s a profound humility in Art’s answer. It recognizes that predicting the success of any innovation is inherently uncertain, and there’s ultimately just one way to find the answer: By whether it works.