Granted, that depends heavily on your features and your data set. It's just as easy to end up with one big undifferentiated blob, even after running PCA.
Granted, that depends heavily on your features and your data set. It's just as easy to end up with one big undifferentiated blob, even after running PCA.
"It's not unlikely that you can say that your data can be partitioned into N distinct clusters."
Of course not...that's tautological. You can say it because that's what it means. DBSCAN isn't some wizardry that peers into the nature of the universe...its just a clump finder. Whether those clumps have any connection to anything interesting is a coincidence. You could roll a six sided die six times and run dbscan on the results and be like "holy shit! I've discovered how to partition the natural numbers 1 2 3 4 5 and 6!!"
Correlation does not imply causation, but you (generally) can't have causation without correlation. Finding natural patterns of associations in data is our only reasonable starting point for finding patterns of causation.
Also, developing reliable and well-researched ontologies can help other researchers when building models, making sense of other data, etc.
Feeding arbitrary sequences of samples into dbscan and deciding that because dbscan produces output, there is causation (or, that there is an underlying phenomena that can be captured in some type of model), is ridiculous. And there are tons and tons and tons of natural phenomena that will be happy to produce clumpable inputs all the time, with no underlying behavior (including noise).
I'm sure there are also tons of interesting models of human behavior that you can make out of some set of observations of human behavior via clustering. But just because you feed some data to an unsupervised learning algorithm and it discovers features doesn't imply that those features have any useful descriptive power to help us make sense of the natural world. THAT's anti-scientific thinking.
So if a causation turns out not to exist then finding natural patterns was an unreasonable starting point? What would have been a reasonable starting point in that circumstance?