Scientific experiments still try to do that. Scientists try to isolate the single variable being tested to be certain their results are valid.
But partly thanks to computer modeling, many scientists are now working on entire systems. The human body is a system. A city is a system. The Earth is a system.
The whole idea of a smarter planet is to use our computing power and the scientific method to solve the problems of systems.
Analyzing genetic code is a massive undertaking, but we can do it now. Analyzing regional transportation is difficult, but doable. Analyzing global climate patterns is also massive, but possible.
The result of using a systemic approach is that you come up with systemic solutions. You need to stop smoking, cut down your drinking, exercise and live right if you're to stay healthy. Cities must be run as regions, political divisions notwithstanding. We have to reduce carbon dioxide if we're to keep the planet temperate.
When people hear such enormous, inconvenient conclusions they rebel. The mechanism for rebellion is politics.
In politics you don't have to be proven right. You engage in a form of show business. You distill complex problems into simple slogans. You build coalitions to achieve power.
Three decades ago, in college, I was a political science major. This was at a time when data, especially survey data, was ascendant. The hope was you could actually make political science scientific.
You can't. Politics is as much art as science. It is not based entirely on reason, but on emotion, and manipulation.
Today's political divides are all about this. One side says the world is complex, that systems are complex, and that solutions must be too. The other side calls this "big brother," and calls for simple answers based on principle.
Ideology, cry the system heads. Elitist, cry the principled.
In the past, science or scientists could easily take either side in political debates. They still can, but only by putting science, engineering, and computing to one side before stepping into the arena.
Systems are the ultimate inconvenient truth. Systems are complex, and any simple solution risks unintended consequences. Fine adjustments and moderation are called for when dealing with complex systems.
Yet at the same time climate scientists see the Earth's system collapsing. For the last few decades they have been very unscientific in their advocacy for enormous changes in mankind's systems for creating and using energy, in order to prevent catastrophe.
Right now, in Copenhagen, scientists are trying to grab the political wheel, knowing that life as we know it is at imminent risk from the go-slow of politics as usual. In response their calls have been politicized. They have been politicized, twisted into caricatures, by people who know that no is always simpler than yes.
Except in this case no means death. We have to treat the system. We can't just treat the symptoms. We have to change course. Politics as usual will kill our grandchildren.
Which means anyone who accepts science finds themselves in a political shouting match with interest groups and ideologues who don't accept the basic premise on which our activism is based.
Smarter planet, meet stupider planet.