Philosophy's map of -isms is far too complex to trace and comprehend. There are many unproductive cul-de-sacs that can be explored before being rejected. Generally, a healthy dose of Pragmatism is essential to avoid the ungrounded species of Idealism and other navel gazing, but let's not throw Idealism out entirely. What is so compelling about a geometric vision of an ideal world that is then projected onto a corrupt and imperfect reality? Why is mathematics so effective in describing the world through the objective, empirical program of scientific discovery? Instead of making ideas and representational reality a primary element, we take the Semiotic modifier and integrate The Ontology of Signs into our conception of the real. Pragmatic philosophers will be happy to have a way for representational thought, and for the entire discovery program of philosophy to emerge from a deeper reality of signs and semiotics.
Being realists means there is a real world that exists and changes according to an internally consistent process. Being pragmatists, we don't expect a necessary connection between our ideas and models and this real world. Whatever its logic is, we expect it is intelligible in some meaningful sense so that, in principle, it could be judged to be consistent. That the world seems to be largely intelligible to us is at the very least surprising, and it would be good to find some structural reasons for it. Science develops this expectation using the assumption of intelligibility to bootstrap primitive guesses into mature theory by using empirical testing. Pragmatic philosophy is behind this process, and in Peirce we find a deep and thoughtful approach to a philosophical grounding of science that is also foundational in pragmatism.
Rational thought is not characteristic of human cognition, but a discovery and exploration of something more universal. Science evolves as an historical, linguistic process where communities of cooperating individuals produce a product that is entirely constructed of signs and their relationships. Peirce positions mathematics not as an external ideal kind of reality, but as a tool for thought; a way to characterize knowledge that is entirely about the relationships of signs with signs as signs. Mathematical knowledge is what can be shown to be always true, so that if you can establish the truth of one group of symbolic relationships, another group of relationships follows. If any of these relationships contradicts another, the entire enterprise fails. Rationality is this mode of thought that judges consistency by developing and expanding the realm of intelligibility. The ideal of Idealism is all of what might be discovered, and we can think of that as an absolute rationality. The real is a particular story that is always incomplete, and all infinities are potential.
Given this background, is it surprising that humanity's development of mathematical knowledge is useful in finding the fundamental physical relationships based upon experimentation? The fact that any of this works isn't because God is some sort of super-mathematician who can do math really fast in parallel to make sure the universe is consistent with God's internal logic, it's because the world actually embodies all the relationsips involved. The world is just being according to its nature. Its nature includes signs and semiotic processes. Math discovers tautological relationships, so alien math might discover different things in different order and express them differently, but the available paths of discovery are there before anyone ever started doing math or being rational.
In the same way that physics is the lowest or fundamental level in the formation and behavior of objects as multi-level whole systems, the multi-level systems of logic, math, science, philosophy and more that constitute what we call rational thought are similarly the unfolding of something more fundamental. That something is relationship, the semiotic triple of sign, object and the actions of interpretation that connect them. Objective reality is constructed with signs. Idealists make the mistake of thinking that reality is contained within this constructed objectivity, and that therefore the physical world is inferior and dependent on an ideal and therefore perfect world. The things that actually do or do not match a particular construction of reality will do what they do whether or not they also become subject to interpretation and objectification in semiotic processes.
When the big bang cools and the particles become cold enough to form stable relationships, they discover nuclear physics and then chemistry. They also discover stellar and galactic dynamics and the large energy structures of quazars as well. This is not being anthropomorphic in saying "discover", it is one aspect of the time dimension of the universe. There was a time when the fundamendal entities of quarks, leptons and bosons were not related as they are later when the higher level structures form. It is a weaker kind of discovery, yet a kind of unavoidable discovery that occurs through the evolution of purely physical structures.
It is arguable that nature doesn't truly discover semiotics until living systems emerge through chemistry. Here we can begin to see signs as active elements of the world. The chemical bonds and structures are now complex enough to form networks of processes, and the products of one process stimulates the next. If certain arangements and structures become autopoetically stable, their operations then define substrates for the action of signs. It is hard to imagine exactly how life emerged from chemistry, but it is easy to see how life uses signs to maintain structure. DNA structures clearly signal the embryo, cells and developing organism to do what they need to do to continue living, and of course we can find signs in nervous signals, imune response, the endocrine system and so much more.
Whether any being becomes capable of discovering the relational dynamics that gives rise to all of these structures is not important to the reality of the actual structures that embody and enact these relationships. If a tree falls in the forest, it does make a sound whether or not it is heard. The vibrations do not require an intelligence to interpret them to have an effect. On the other hand, there is a reality to the fact of hearing the sound; the presence of a being that can and does hear it. When we shout hello to the universe, is anyone hearing us? If they do, I hope they want to be friends.
To summarize our metaphysics:
The objects we have discovered are the objects of modern physics, and form the basis for building everything else. Emergent structures at each scale will have signs, objects and interpretations with the same metaphysical status of those at any other level. They will be a lot simpler at the lower scales, and often all the possible states and behaviors are well represented in the world accessible to observation. At the higher scales there are a lot more possible states and paths than can be explored and potentially reached.