Saturday, June 30, 2007

Copernicus is My Favorite Pattern In interviews it's common to ask "What's your favorite and least favorite pattern?" My usual answer for favorite pattern is "keep separate things separate." It's a bit meta  which allows me to talk about a few design principles that are dear to me. My least favorite pattern is the wretched visitor pattern because it binds together different parts of an application that have no business even knowing about each other. It creates a BLOB. After having read "It Started with Copernicus" by Howard Margolis I am going to have a new favorite pattern: the Copernicus Pattern. I will always hate the visitor pattern, so my answer to that question is not likely to change :-) The premise of this book is that Copernicus' discovery of the heliocentric model of the solar system started a fire storm of scientific invention, not because of the discovery itself, but because it spread the idea that we puny humans could think and make big discoveries about the universe using  nothing but our tiny brains. Copernicus gave people permission to tackle big challenges and the confidence that they could expect to meet them. As evidence Margolis lists the major scientific discoveries made before 1600 and the major scientific discoveries made after 1600. Copernicus published his "discovery" that the Earth revolves around the Sun in 1543. In the list of pre-1600 major discoveries there is: nothing. Zip. Nada. After 1600 the pace of scientific discovery blossoms, we discover: the distinction between electricity and magnetism; law of free fall; Galilean inertia; Earth is a magnet; theory of lenses; laws of planetary motion; various discoveries from the telescope, like sunspots; laws of hydrostatic pressure; and synchronicity of the pendulum. All these discoveries were made by Stevin, Gilbert, Kepler, and Galileo all followers of Copernicus. Copernicus discovered discovery using what Margolis calls "around the corner" reasoning. Around-the-corner-reasoning is a habit of mind where you go beyond what is directly seen and take the unexpected step. Stubborningly pursuing a problem even when no clear solution is in sight. Before 1600 most things that can be discovered by direct ways of thinking were discovered. After Copernicus around-the-corner-reasoning helped us start discovering how the world really worked. I highly recommend the book if you want to see a full development Margolis' argument. My already long delayed point follows a similar line of reasoning... What is important about patterns is the idea of patterns and not any particular pattern itself. Many have pointed out the weaknesses of patterns. Patterns can seem like trivial well understood solutions to common problems. Patterns can appear overly formal and lead to complex systems of frameworks that complicate more than they help. Patterns can pollute your code and lead you away from doing the simple thing. For me finding and using patterns is essential because patterns are simply software systemizations. A pattern is that bit of around-the-corner-reasoning that can create massive simplifications and improvements in your system, if you would just take the time to understand your system, see what's really going on, and think a bit how it might be improved. Programming isn't just writing one damn line of code after another. Patterns are the idea that you can continually find ways to  make your system better. If that's using the publish-subscribe pattern, resource acquisition is initialization pattern, or whatever, it doesn't matter. What matters is the idea that a system evolves over time to have inefficiencies and that the system can be brought under control again by  systematically applying patterns of improvement. comment[] 4:29:33 PM       digg   reddit

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