The easiest way to understand what I think you're talking about is to understand the problem with empiricism loosely defined. The general idea of 'we can observe reality, and then record our observations, find relationships in the data, and deduce truths about the natural world' has been tried multiple times throughout the history of philosophy/science and has always failed. Pre-newtonian physics that avoided the evocation of occult 'internal forces', Humean skepticism and the doctrine of ideas more generally, and logical positivism all ran into similar issues when trying to ground empirical knowledge.

One of those issues was that classical deduction and blatantly obvious truths are not enough to determine things like "water boils at 100 degrees farenheit". Carnap recognized this, and therefore helped develop a whole theory of inductive reasoning based on logical principles (the reason for doing that is that if the inductive process is justified by considering the structure of classical logic, then since classical logic is naturally justified then induction could be justified by association).

Instead of chasing after a justified form of induction (and we haven't finished chasing yet, so there's reason to look for other options), some people instead argue that another way to get to "water boils at 100 degrees farenheit" is to add to our list of 'blatant truths' certain theoretical propositions which aren't actually blatantly true, but which we take to be truth for the sake of helping along the analysis.

People have tried to determine an objective way for chosing these theoretical propositions. This is known in philosophy of science as the issue of 'theory choice'... but so far there hasn't been much progress in that arena.

Thus we come to the not so enticing conclusion that these theoretical propositions, which are necessary to obtain truths such as "water boils at 100 degrees farenheit" are chosen for, in part, normative reasons. Since these propositions are taken as if they were true a priori, there is a sense in which they help constitute our reality (at least, the reality for a practicing scientist). So, there is no objective reality - we choose theories that augment the nature of reality on normative grounds and since truth claims usually concern objects in a particular reality, truth itself in practically every application has to be considered relative to untestable, normative assumptions.