My advisor is a huge, huge fan of "lightning empiricism." It's a term I haven't heard anywhere else, and my advisor says he got it from HIS advisor. Basically, it's a more-scientific-sounding way of saying, "go try it and see." Physically parking your butt at a lab bench and trying something, usually as simply and easily as you can, has huge benefits. Often you'll find out something you never would have anticipated without getting your hands on it.
You can also think about it like this: When you apply the principle of "just try something simple" to doing analysis, you call it back-of-the-envelope calculations. When you apply the principle to doing experiments, you call it lightning empiricism.
The point is, sometimes it's not worth spending hours poring over theory and simulations, if there's something you can do to test the basic concept. If the basic, quick-and-dirty tests are successful, or teach you something by their failure, then you can move forward with that new knowledge. I really like that my advisor pushes the hands-on learning; a lot of professors I know rely much more heavily on the theory.
I have to share a story here, which you can skip if engineering isn't your field: For instance, I was having trouble with a basic op-amp circuit I had built that was not behaving correctly - it was supposed to double the input voltage, but it wasn't working over the whole range. I asked one of my friends about it, and he dove right into circuit calculations and Kirchoff's rules to see if we could figure out what to change. But when I asked my advisor, the first thing he said was, "Did you put an oscilloscope on it?" Well, no, I hadn't - I just used a multimeter, since it was a DC signal. So he wouldn't talk to me until I trotted back to lab, and took a look at the actual analog signal. Lo-and-behold, my cheap power supply was fluctuating. Well THAT would never come up in the theory.
Anyway, I've been doing this lightning empiricism stuff for my research all summer. I found the papers in literature that showed something really cool, and I've been trying to replicate or improve on the same technique. But I've tried LOTS of different parameters, and it's still not working. Step 1, apply ink to stamp. Step 2, stamp pattern onto substrate. Endless variations on those two steps, and I still haven't come up with something halfway decent, even though I think I'm doing everything exactly as I find in literature.
So this is where lightning empiricism reaches its limits. Simply throwing darts at the problem isn't working, and I don't have time to keep flailing around until I happen to hit on something that works. If I've tried everything I know to try, and I still don't understand what's going on - then that's exactly what I'm left with. I don't understand what's happening.
And that is where I have to go back to theory. Back-of-the-envelope is no longer good enough, I need to have a deeper understanding of the fundamental concepts.
So I'm going back to the literature, learning more about the physical process of fluid transfer, surface-chemical interactions, and the work of adhesion. Simply dipping my toes into this world of literature has already maxed out my knowledge of chemistry, so it's going to be a mental stretch for me.
But let's face it, it wouldn't be much of a PhD if all I had was lightning empiricism - kind of the whole point is to have a deep understanding, right?