[dusklight]

All I know about causation and correlation I learnt hunting bugs in large legacy software systems. In that environment I got the impression that correlation almost never equalled causation, but that's only because the hardest bugs, the ones I remembered, were hard because the obvious correlations did not help identify the root cause. A similar argument might be made for scientific studies: most of the easy causes that can be identified from correlation have already been found, leaving the majority of new studies with correlations that don't easily establish causation.

[api]

I think this low-hanging-fruit idea is generally true for all of science: after centuries of science as a profession, pretty much all the easy stuff has already been done.

It's actually an argument for more cojones in science-- being willing to do bold stuff and explore "crazy" hypotheses. If all the easy stuff is done already, then picking methodically and timidly among the dregs is unlikely to ever yield anything.

[mattfenwick]

An alternative viewpoint: everything's easy after it's been done, but it's hard up until then.

> after centuries of science as a profession, pretty much all the easy stuff has already been done.

But with the benefit of all that has already been done, shouldn't we be able to do things now that were previously impossible? In other words, "easy in 2014" != "easy in 1200".

> It's actually an argument for more cojones in science-- being willing to do bold stuff and explore "crazy" hypotheses.

Maybe doing whatever's easy is the most efficient (by time, money) way to make progress?

[api]

I'm not sure... seems like what you say may hold for a while, but eventually you start hitting a more objective sort of hard: things that are hard for human beings to comprehend due to the limitations of our intelligence itself. Beyond that there's probably an even harder hard-- when you start actually running out of new things to discover. Can there really be an infinite number of physical laws, principles, and useful relations? Or at some point have you actually found most of basic physics?

Once you start hitting those, you've either entered a permanent era of diminishing returns or one where you can only really make progress by radically redefining problems, making leaps, or trying wild and crazy ideas in the hopes of unlocking some isolated seam of high-value research that isn't connected to the others in the fitness/value state space graph.

[mattfenwick]

Sure, we can't rule out those possibilities ... but to me it just sounds like wild speculation.

[ScottBurson]

Yeah, debugging is great training in the scientific method.