A lot of theologians and religious thinkers advance the idea that in order for any position to have meaning in epistemology or ethics or metaphysics it is necessary to interpret reality through some sort of Weltanschaung, pre-established worldview. Thus facts in and of themselves are meaningless unless looked at through the correct theory. Which secular philosophers and traditions examine this type of "worldview" thinking?
Well, AntiMorello, I'm going to offer some leads. I consider the question metaphilosophical because in effect, most traditions or schools in philosophy essentially offer some first principles which might be considered normative regarding how to construct a worldview. Some philosophies are notoriously anti-intellectual, but on the whole, most philosophers have some, what might be termed metaphysical systems, that they offer in regards to building theories for axiological, ontological, mereological, and epistemological preferences. To Aristotle, eudaimonia along with vice and virtue was the framework offered. Immanuel Kant offered a non-theological transcendental idealism as a worldview and a framework for ethical considerations categorical imperative. So on and such like.
But if you are talking about modern secularism, then I propose three programs of investigation:
Logical Positivism and Post-Positivism
First, closest to my heart are the writings of the logical positivists because their program infamously specifically sought to eliminate metaphysics entirely. While they failed, they made some gains in epistemology such as advancing the thesis that model-theoretic reasoning is a necessary part of a secular worldview, and took up the language of philosophy in spades as well produced a vast body of literature regarding the demarcation problem of science. As a proponent of a moderate scientism myself, this tradition contains too many geniuses to name in logic, mathematics, language, and science. In effect, the work built on Frege and Hilbert has continued to produce knowledge in the same spirit as Comte's positivism. In this tradition, philosophers advocate for an objective worldview.
- A.J. Ayer put together called logical positivism - An anthology of introductory works
- A Nice Derangement of Epistemes by John H. Zammito - A great history of the after-effects of the failure of logical positivism and a reflection on what the sciences currently are understood to be.
- The Linguistic Turn by Richard M. Rorty - An anthology of work about the linguistic turn. With scientism, there's a rejection of metaphysical speculation, deepities (YT), and verbal woo.
Existentialism and Absurdism
Existentialists advocate and study a worldview built around life after the existential crisis and dealing with existential guilt. While existentialism doesn't endorse atheism, it does advocate that regardless of your belief system, you must become authentic and become your best self. In this humanist worldview which is also very psychological, and which has a tremendous impact on clinical psychology, you are constantly called to deal with building meaning. In the extreme form, Camus, who rejected the label of existentialist, did advocate atheism, and insisted that under the oppression of having to determine one's own purpose and values, the best response was a visceral, sensual rebellion against absurdity and society in a metaphorical sense. In this tradition, the worldview is a product of the self.
- Being and Nothingness by Jean-Paul Sartre - Tough read, but the best explication of his philosophy. Some of his other books are far easier to read, but oh well.
- The Myth of Sisyphus by Camus - This book is the most poetic of the three recommendations. Reading Camus is closer to the stream of consciousness of Tennessee Williams than the technical philosophy in the analytic current and absurdism demands the most internal locus of control.
- What is Called Thinking by Martin Heidegger. - Far easier than his earlier magnus opus, and more playful, it explicates on his system Being and Time.
Philosophical Anthropology and Social Reality
I think this might be closest to what you are referring to, because here the worldview is specifically viewed as a social product to be scientifically studied. The study thereof is known as social constructionism. I know the least about philosophical anthropology, but can say that as an analytical thinker by constitution, it's the most challenging because of how serious it takes its phenominological roots. Looking at how the philosophy of language views the matter one starts off with semantics, pragmatics, and propositional attitudes and the like and then can develop a full-blown theory on how we talk ourselves into society as well as how society molds us into citizens. This tradition might be seen as tackling the social enterprise of building a worldview.
- The Construction of Social Reality by John Searle builds on his earlier work regarding intentionality and other interests in the philosophy of language.
- The Social Construction of Reality by Berger and Luckman is a tough read, but it's interesting because it purports to deliver a theory on how society mechanistically creates cogs in the machine.
- Levels of Organic Life and the Human by Helmuth Plessner (Danke, Mein Herr!) is the most foreign to me, and I've only partially read it. Like a lot of the German greats, you have to develop an entirely new vocabulary out of words you already use. But it's good to force yourself out of your philosophical tribe (mine being sympathetic to ordinary language philosophy) to grow your intellect.
Like I opened, philosophy particularly since Cartesianism, strongly focuses on developing a worldview, and no more was that present in the sweeping metaphysical speculations of Kant and German Idealism. The three threads I've laid out take both "Anglo-American" and "Continental" traditions into account, but are not exhaustive. I didn't recommend the Parisians like Derrida or the Frankfurt School mostly because I don't have much experience in them. Perhaps their take on worldview would be more to your liking. There's also Chinese, Japanese, and Indian traditions, but I know almost nothing about them. But whatever you do, read, read, read. You'll start to see how all of these theories seem to save the same purpose: ease you into a worldview of your own making.
The origin of the term weltanschaung in philosophy goes to Kant, and was developed further by Hegel, and in their work led to a subtle divergence from the English cognate 'worldview'.
I would look to Kuhn's paradigms, for an example of how models of reality shape what we experience, with changing our model of reality in ways discontinuous with the old model, leading to experiencing a different reality or paradigm. People become invested in a worldview, and the consequences they feel it has for them and the community that holds it.
Durkheim's picture of sociological truth, developed to account for religion as the binding together of communities by shared enactment of what is held sacred or put beyond question, can help us understand this. The scientific community has a culture of truth-making, and fulfilling it's obligations grants access to a community with costs and benefits, and ignoring it's requirements can lead to excommunication from benefits of being in the community.
Thus facts in and of themselves are meaningless unless looked at through the correct theory.
I don't agree with that. It implies there is an unlimited subjectivity to truth determination. Choosing to ignore a scientific theory, like say the Nazis refusing to accept Relativity as 'Jewish science' does not grant the option of ignoring the facts, like say of nuclear fission bombs. We might link this to what seems to have been inevitable costs of a propagandist's picture of facts, that it causes holders to ignore real possibilities, both apparently negative one's, but also positive (eg reducing real tensions that undermine cooperation).
It is not the facts which depend on theory per se. You could argue that "The world is the totality of facts, not of things", and there is a cultural aspect to determination of facts, like say by double-blind controlled trials. I think though we should accept Poppers picture that our worldview is not assembled from facts, that instead we develop theories, systems of abstraction, and distinguish between them using facts - being relatively indisputable data, or data determined by a Socratic discourse of mutual attempt to find the best answer.
I link what we find to be true, to 'running' a circumstance through our model, and comparing the real output to our expectation: Why is a measured true value “TRUE”? From that answer:
The real problem is our intuition that 'true' always means getting to look behind the curtain - 'getting our homework marked by god'. When we think hard though, we find 'true' isn't in the 'facts', it is in the whole situation of evaluating them, and never stand separately from them.
We seek to reconcile truths into one model, linked to the unity of our experience of subjectivity, and intersubjectivity: Why is it impossible to hold both horns of a moral dilemma?
It's interesting to note Hegel's distinction recently discussed on this SE, between real and actual, a category of quality vs modality, the opposite of real being a negation, the opposite of actuality being possibility. What is real we can assign to the domain of facts. What is actual, to what our theories allow, tested against what we find to be real.
I would point to the termination of Hilbert's objective to fully axiomatise physics with Godel's Incompleteness Theorems, to the impossibility of having a 'finished' complete picture of reality, varifiably superior to any others. We can link this to Turing machines seeking decidability, vs minds seeking explanatory power, discussed here: One big theory of Everything (TOE) or multiple "domain specific" theories? We might say AI so far has addressed determining the real outputs of the theories, and minds work with what is possible. This makes me optimistic about Deutsch and Marletto's Universal Constructor Theory, which seeks to address this (also see Deutsch's book The Fabric Of Reality for an interesting attempt to synthesise a modern scientific weltanschaung, I do think this is a valid thing to attempt, even if Godel Incompleteness means we will always be limited to creating tangled hierachies, Hofstadter's strange-loop picture of different domains of concern leaning on each other like a coherentist fabric, rather than a foundationalist tower).
We might say facts are 'atomic' or simple truths, that require assent to easier things to agree to. Then we have theories, which reconcile whole domains of facts (see 'the journey of unification' of physics discussed here: Is the idea that "Everything is energy" even coherent?). Then we have worldview, our assembly of theories, both of scientific material matters, but also cultural sociological truths, like Durkheim examined. The benefits of intersubjectivity, of expanding our minds through treating other humans 'as if they were us'. We can relate this to the social reification of models of our identity, discussed here: Why is it impossible to hold both horns of a moral dilemma?
I prefer the term 'cosmology' to 'weltanschaung'. In the modern sense, cosmology is a domain mainly for astronomers. But the origins of everything, non-human minds, and where we are in relation to everything else, is a perennial concern of cosmologies. What is I think different to weltanschaung, is that cosmologies have at root situating ourselves within what we know, our assembly of theories in the widest sense. Can the Universe make sense at all? As we go 'up' the hierachy of scale we get to the Big Bang which can reveal things about the finest structure of matter, as we go 'down' in scale we understand properties that shape stars and black holes and impact the long term fate of the universe. The cosmic distance ladder shows how nested the structure is, and each layer has consequences not just for above and below in scale, but for development and future of the cosmos. Humans happen to be about halfway in logarithmic size between the whole universe and the Planck scale, whether that is coincidental or not. Surely it is interesting minds have occurred there, with potential to reach consequences across space and time. Who we are, who we can become, deeply relates to what paradigm we have for situating ourselves.
What I like most about the term cosmology or maybe meaning-cosmology to clarify not just astronomy, is we can explicitly link it to Hofstadter's picture of tangled hierarchies, with many domains investigating and elaborating each other in dynamic ways, and we can link that to strange loops, the emergence of something 'mind like' from running circuits or loops through our structure, not as a fixed thing of truth or negation, but with attention to the possibilities involved. I think Hegel might approve of this as a modern picture of 'geist', the experience of an individual of engagement with the becoming of an intelligence that transcends their individuality. But we can shed the racist nationalism that Hegel and followers directed this to, while still picturing the accrual of cultural intelligence which may be it's own justification.
From Heidegger's Contributions to Philosophy (of the Event)
A "worldview" sets experience on a definite path and within a determinate range, and this in such a broad way that it does not allow the worldview itself to come into question; the worldview thereby narrows and thwarts genuine experience. From the standpoint of the worldview, that is precisely its strong point.
This is an examination of "worldview" thinking in repudiation of interpreting reality through some sort of pre-established worldview.