As Testers, How Do We Know What We Know?


rise in the east tomorrow; we merely have an extremely high confidence that it will, based on our having observed it having done so and the fact that it seems to conform to our tested theories about how heavenly bodies work. Scientific theories often hold up for many decades or centuries but are later discredited in the face of more complete knowledge. Thus, we must never close our minds in thinking we know something, but always be open to new information that alters what yesterday we deemed well-nigh certain.

 Check out the other articles in Rick's series on philosophy and software testing:

User Comments

Sanat Sharma's picture
Sanat Sharma

A great article bridging the gap between philosophy and technology. I read this article thrice to have a deep understanding of it. But sometimes, I got confused about what the author is trying to say.

-- Sanat Sharma

August 16, 2011 - 1:24am
Gerard Miller's picture
Gerard Miller

Hi Rick,

Excellent article. Sometimes what we know is true may not be true all times in all conditions. The context is real-time systems.


From Jack Ganssle article from 7/29/2011

For instance, what is the likelihood the sun will rise tomorrow? Dumb question; for four billion years the probability has been 1.0. Surely it's safe for an engineer to think that the sun will indeed appear tomorrow as it always has. Five or six eons from now it will be a burned-out cinder, but our systems will be long landfilled by then.

Recently a developer told me about a product he worked on that changed the display's color scheme depending on whether it's night or day. It does a very accurate calculation of sunrise or sunset using location data. Turns out, a customer took one of the units above the Arctic Circle where it crashed, the algorithm unable to deal with a sun that wouldn't rise for months.

The sun may not rise tomorrow. Don't count on anything.

August 16, 2011 - 8:53am

About the author

StickyMinds is a TechWell community.

Through conferences, training, consulting, and online resources, TechWell helps you develop and deliver great software every day.