This is what the average non-scientist thinks of science. Scientists are a bunch of crazy-smart men (and to a lesser degree, women) who wear white lab coats and hold vials of brightly colored liquid in photogenic poses. Science produces all these cool technologies: computers, robots, death rays, etc. Science is a lot like magic, only more futuristic. When people think about science, they equate it with transhumanism: "Wow, science has given us so much power--but whether it is good or evil depends on how we use it. Is the human race truly ready for so much change?"
The obvious problem with this view is that it ignores the process of science (I'd also quibble about the transhumanism bit, but another day). Scientists don't just instantly produce shrink rays out of no where. To most people's credit, they do seem to realize that science involves curiosity, knowledge, and calculations. But there's still more to it than that.
The Scientific Method
In this view, science is all about the scientific method. Look at the world around you, and create a hypothesis. Make predictions from the hypothesis, and test it against the real world. If the test fails, reject or modify the hypothesis. Repeat. Always repeat. Of course, science doesn't actually work that way, step by step, in exactly that order. More broadly, science is simply about combining empirical observations with reasoning, and being forever willing to reconsider previous conclusions.
The reason people like this broad definition is because science becomes a "way of knowing." And then you can compare it to religion or faith. Depending on who you ask, you might get one of these answers: (1) Religion is just another way of knowing (2) There might be other ways of knowing, but religion isn't one (3) Science is the only way of knowing.
Now, on my second day of blogging, I argued number (3). I stand by it. But I have reservations about using such a broad definition. If all of reasoning falls under science, then I would have to include lots of things that aren't normally considered science: economics, politics, certain kinds of liberal arts, philosophy, ethics, parts of theology, as well as a bunch of everyday activities. This is ultimately confusing. If politics is a science, it sure isn't much like the rest of science. At worst, I could be accused of the equivocation fallacy.
I often think that instead of saying "science" when we mean "observation plus reason", we should just say "observation plus reason".
Science: what scientists do
This is the definition used by most working scientists. I'm putting it last because I obviously think it's the most correct one. Science is what scientists do. It's what you learn when you study science. It includes both the body of knowledge resulting from science, as well as the methods and reasoning used to get there. It also includes the people themselves, and the scientific establishment.
Science isn't just about empirical investigation along with abstract reasoning--I can do that on a blog. What I won't do on a blog is publish scientific papers in peer-reviewed journals. I won't conduct rigorous studies complete with control groups and statistical analysis. I couldn't do any of that here, because it would be the improper route. None of these conditions are necessary to acquire knowledge, but they are necessary for science.
That's right, I said it. Science isn't everything! *hides from killer robots*