It kinda depends.
I think of my notions as largely post-conceived, based on the assessment of facts over many years.
But you are right that having post-conceived notions, they become pre-conceived as they are reapplied!!
So I guess it is a mixture.
But I guess the idea we have been discussing is - should a person test their conceptions against new observations, rather than vice versa. And my answer is - yes, always. The temptation is to make facts subsidiary to theories. But the proper method is always to check.
So - my preconception on healthcare was that the US system was relatively sound and that the large amount of money it costs likely paid for a better quality of service.
I then looked at the fact base.
And after thinking about it, I realised my preconception was specious.
I wondered why. And the more I looked, the more I realised the problems are structural. Private insurance and free market dogmas are in conflict with the underpinnings of medical tradition, which isn't exclusive and recognises the value of the combination of private and public goods.
In the end, some portion of altruism and inclusiveness is efficient. We see this in the healthcare marketplace.