In the philosophy of science it may refer to the acceptance of co-existing scientific paradigms which though accurately describing their relevant domains are nonetheless incommensurable.
In ancient Greece, Empedocles wrote that they were fire, air, water and earth,[7] although he used the word "root" rather than "element" (στοιχεῖον; stoicheion), which appeared later in Plato.
[8] From the association (φιλία; philia) and separation (νεῖκος; neikos) of these indestructible and unchangeable root elements, all things came to be in a fullness (πλήρωμα; pleroma) of ratio (λόγος; logos) and proportion (ἀνάλογος; analogos).
His metaphysical system is centered around mechanically necessitated nous which governs, combines and diffuses the various "roots" of reality (known as homoioneroi[9]).
Unlike Empedocles' four "root elements" and similar to Democritus' multitude of atoms (yet not physical in nature), these homoioneroi are used by Anaxagoras to explain the multiplicity in reality and becoming.
The notion of a governing nous would also be used by Socrates and Plato, but they will assign it a more active and rational role in their philosophical systems.
His hylomorphic theory allowed him to maintain a reduced set of basic material elements as per the Milesians, while answering for the ever-changing flux of Heraclitus and the unchanging unity of Parmenides.
Eklund has argued that Wittgenstein's conception includes as a special case the technically constructed, largely autonomous, forms of language or linguistic frameworks of Carnap and Carnapian ontological pluralism.
He places Carnap's ontological pluralism in the context of other philosophers, such as Eli Hirsch and Hilary Putnam.
All that is required of him is that, if he wishes to discuss it, he must state his methods clearly, and give syntactical rules instead of philosophical arguments.