- scientific knowledge is embedded in some intellectual ether made of underlying hypotheses often not explicitly stated called paradigms
- paradigms follow a Darwinian evolutionary process, i.e. better paradigms evolve out of not-so-good previous paradigms
- paradigm replacements start with an epistemological crisis , i.e. facts that the current paradigms don't explain well enough.
Hope it helps !
If you believed the world is flat you can still get from one village to the next one and you wouldn't fall of the earth. It's true enough for what it is trying to accomplish. If you want to navigate longer and longer distances or go to the moon however this believe will meet it's limits.
The primary thing people struggle with in general with science and philosophy of science is actually more fundamental in other parts of life to which is Truth.
Popper thought science helped us approach the some objective Truth. Kuhn realized (and I agree) that truth is always depending on the context in which it's defined.
We don't need truth we just need useful.