One of the most overriding concerns of Christians who've commented on the debate between Bill Nye and Ken Ham has to do with the presuppositions operative in the worldviews of each man. In the days of the logical positivists, we saw that this was described as the concept of theory-ladenness. Karl Popper, very much like contemporary Christian presuppositionalists, argued against advocates of a kind of naive empiricism, that there is no such thing as purely impartial and unbiased interpretation of evidence. To put it in the language of the analytic philosophers of his day, all observation is theory-laden. Following the demise of the logical positivists, this becomes an increasingly important point made in philosophy in general, and especially philosophy of science. While among some philosophers, this emphasis became such an overriding concern that it came to constitute the essence of their philosophy, such that any interpretation of anything whatsoever could always be totally reduced to the presuppositions inherited by the interpreter's historical context, we will be focusing more specifically on philosophers of science who appreciated the importance of understanding that all interpretation entails some form of bias.
For the philosophers under consideration, the question was broadly one of holism. Scientific theories always take place within a specific context. It is because of their inseparability of (but not their reducibility to) such a context that observation, and theorizing about such an observation, is always theory-laden. To be context-laden is to be theory-laden. The most sophisticated articulation of this historical and sociologically sensitive approach to the examination of scientific theories took place within the work of Thomas Kuhn and Paul Feyerabend. Indeed, "Since 1962, the incommensurability of scientific theories has been a widely discussed, controversial idea that was instrumental in the historical turn in the philosophy of science and the establishment of the sociology of science as a professional discipline"(Oberheim 2013)
The notion that scientific theories could be "incommensurable" began with Thomas Kuhn's publication of his now-famous work, "The Structure of Scientific Revolutions." Kuhn
In the influential The Structure of Scientific Revolutions (1962), Kuhn made the dramatic claim that history of science reveals proponents of competing paradigms failing to make complete contact with each other's views, so that they are always talking at least slightly at cross-purposes. Kuhn characterized the collective reasons for these limits to communication as the incommensurability of pre- and post-revolutionary scientific traditions, claiming that the Newtonian paradigm is incommensurable with its Cartesian and Aristotelian predecessors in the history of physics, just as Lavoisier's paradigm is incommensurable with that of Priestley's in chemistry (Oberheim 2013)
Kuhn argued that the scientists of each age "use different concepts and methods to address different problems, limiting communication across the revolutionary divide"(Oberheim 2013). For Kuhn, scientific investigation did not progressively approximate the truth. He denied that we could intelligibly conceive of science as
"an improving approximation to the truth, and to challenge the idea that there are unchanging, neutral methodological standards for comparing theories throughout the development of the natural sciences. Like in evolution, the process does not change toward some fixed goal according to somef ixed rules, methods or standards, but rather it changes away from the pressures exerted by anomalies on the reigning theory...The process of scientific change is eliminative and permissive rather than instructive. In the process of confronting anomalies, certain alternatives are excluded, but nature does not guide us to some uniquely correct theory (Oberheim 2013).
As we noted before, Kuhn's approach was not quite the same as the postmodernists. His point was largely an attack on the logical positivists and logical empiricists before, according to which "comparing theories requires translating their consequences into a neutral observation language"(Oberheim 2013). New theories require a new vocabulary, which the older vocabularies are unable to accommodate. This is "taxonomic incommensurability." It was understood as resulting "in translation failure between local subsets of inter-defined terms due to the cross-clarification of objects into mutually exclusive taxonomies"(Oberheim 2013). In other words, scientific theories and paradigms are clusters of mutually defining and mutually dependent terms whose relations must be radically altered in order to accommodate a new theory.
On the other hand, we have what is known as "methodological incommensurability." To discuss methodological incommensurability involves "the sense that theory comparison is sometimes a matter of weighing historically developing values, not following fixed, definitive rules"(Oberheim 2013). In other words, there is no monolithic, static scientific method. Scientific method consists of a set of loosely related but distinct and non-essential practices of investigating the natural world. There is no definitively correct or incorrect way of doing science. "This makes room for rational disagreement in theory comparison, as scientists may apply different values (such as scope, esimplicity, fruitfulness, accuracy) in evaluating and comparing particular theorires, so that theory choice is not unequivocally determined throughout the scientific community" (Oberheim 2013).
1962 was a big year for scientific incommensurability. Not only did it see the publication of Thomas Kuhn's "The Structure of Scientific Revolutions," but also that of Paul Feyerabend's "Explanation, Reduction and Empiricism." Like Kuhn, Feyerabend was preoccupied with the question of holism in scientific reasoning.
"He argued that in the course of scientific advance, when fundamental theories change, meanings change, which can result in a new conception of the nature of reality. By calling two fundamental theories incommensurable, Feyerabend meant that they were conceptually incompatible: The main concepts of one could neither be defined on the basis of the primitive terms of the other, nor related to them via a correct empirical statement...For example, Feyerabend claimed that the concepts of temperature and entropy in kinetic theory are incommensurable with those of phenomenological thermodynamics (1962, 78); whereas the Newtonian concepts of mass, length and time are incommensurable with those of relativistic mechanics (1962, 80). Feyerabend repeatedly used the idea of incommensurability to challenge a wide range of forms of conceptual conservativism, arguing that they unjustifiably favor successful, entrenched concepts over potential improvements, overlooking the possibility of developing incommensurable alternatives (Oberheim 2013)
Kuhn and Feyerabend both had their predecessors in the work of Duhem, Ajdukiewicz, Poincaré, Bachelard, Fleck and Canguilheim, but their accounts of scientific incommensurability remain the earliest articulations of the concept, and we will be focusing primarily on their works. Kuhn's articulation of his understanding of the epistemic status of science was later revised in order to counter certain misinterpretations of his work. Kuhn was an example of what we have previously referred to as "holism." To reiterate our previous point in explaining what this means, scientific investigation always takes place within specific definite contexts. Scientific investigation, to put it more simply, is never merely neutral.
Kuhn initially used the term holistically to capture methodological, observational and conceptual disparities between successive scientific paradigms that he had encountered in his historical investigations into the development of the natural sciences (Kuhn 1962, 148–150). Later, he refined the idea arguing that incommensurability is due to differences in the taxonomic structures of successive scientific theories and neighbouring contemporaneous sub-disciplines. Kuhn's developing notion of incommensurability has received much attention, and it continues to provoke plenty of controversy (cf. Bird 2007, Demir 2008, Moreno 2009, Psillos 2008, and Soler, Sankey and Hoyningen-Huene 2008) (Oberheim 2013)
Kuhn's central emphasis throughout his career, even when important discontinuities and developments are noted, is the importance of holism. Earlier on, he emphasized incommensurability as involving the impossibility of communication between scientific theories of distinct epochs whose conceptions of the world were fundamentally different. While he later modified this position, it is clear that even his revised beliefs center around the importance of understanding scientific theories in terms of mutually dependent, mutually reinforcing groups of beliefs which go into making up the contextually constituted nature of one's worldview.
For Kuhn, when a scientific revolution takes place, certain holistic man's conception of the world take place. Things that used to be problems became nonsensical non-issues, and problems of which previous generations could not even conceive were generated by new discoveries. More interesting yet, scientific theories which exhibit epistemological incommensurability because they consist in a radically different conception about reality, also exhibit methodological incommensurability, insofar as they differ concerning what constitutes good or authentic science (Oberheim 2013).
Newton's theory was initially widely rejected because it did not explain the attractive forces between matter, something required of any mechanics from the perspective of the proponents of Aristotle and Descartes' theories (Kuhn 1962, 148). According to Kuhn, with the acceptance of Newton's theory, this question was banished from science as illegitimate, only to re-emerge with the solution offered by general relativity. He concluded that scientific revolutions alter the very definition of science itself (Oberheim 2013).
For Kuhn, the dynamic nature of scientific paradigms entailed a semantic holism as well:
"Changes in problems and standards come with corresponding conceptual changes, so that after a revolution, many (though not all) of the older concepts are still used, but in a slightly modififed way. Such conceptual changes have both intensional and extensional aspects, which is to say that the same terms take on different meanings and are used to refer to different things when used by proponents of competing incommensurable theories. The changes in the intensional aspects of concepts result because the terms used to express a theory are inter-defined and their meanings depend on the theories to which they belong. For example, the meaningts of the term 'temperature', 'mass', 'chemical element' and 'chemical compound' depend on which theories are used to interpret them. Conceptual changes also result in the exclusion of some old elements of the extension of a concept while new elements come to be subsumed by it, so that the same term comces to refer to different things. For example, the term 'Planet' referred to the sun but not the earth in the Ptolemaic theory, whereas it refers to the earth and not the sun in the Copernican theory. Incommensurable theories use some of the same terms, but with different meanings, to refer to different sets of things. Two scientists who perceive the same situation differently, but nevertheless use the same vocabulary to describe it, speak from incommensurable viewpoints"(Oberheim 2013)
More controversially, Kuhn argued that scientific training within the context of a specific scientific paradigm radically conditioned the way scientists reflexively interpret events.
where a proponent of the Newtonian theory sees a pendulum, an Aristotelian saw constrained free fall; where Priestley saw dephlogisticated air, Lavoisier saw oxygen; where Berthollet saw a compound that could vary in proportion, Proust saw only a physical mixture. Kuhn (and Feyerabend) used the analogy of a Gestalt switch to illustrate this point. In this way, one main source of the notion of incommensurability of scientific theories has been the development of Gestalt psychology (Oberheim 2013).
"According to Kuhn, these three interrelated aspects of incommensurability (changes in problems and standards that define a discipline, changes in the concepts used to state and solve those problems, and world change) jointly constrain the interpretation of scientific advance as cumulative. Scientific progress, Kuhn argued, is not simply the continual discovery of new facts duly explained. Instead, revolutions change what counts as the facts in the first place. When reigning theories are replaced by incommensurable challengers, the purported facts are re-described according to new and incompatible theoretical principles. The main goal of Kun's Structure was to challenge the idea of scientific progress as cumulative, according to which what is corrected or discarded in the course of scientific advance is that which was never really scientific in the first place, and Kuhn used incommensurability as the basis of his challenge" (Oberheim 2013)
Kuhn traces his own discovery back to his days of a graduate student. Reading Aristotle's writings on motion, he was astounded by how foolish some of Aristotle's statements seemed, particularly in relation to how brilliant Aristotle clearly was. Thus, Kuhn
realized that in his earlier encounters, he had been projecting contemporary meanings back into his historical sources (Whiggish history), and that he would need to peel them away in order to remove the distortion and understand the Aristotelian system in its own right (hermeneutic history). For instance, when he encountered the word “motion” in Aristotle (the standard translation of the Greek kinesis), he was thinking in terms of the change of position of objects in space (as we do today). But to get more closely at Aristotle's original usage, he had to expand the meaning of motion to cover a much broader range of phenomena that include various other sorts of change, such as growth and diminution, alternation, and generation and corruption, making an objects motion in space (displacement or ‘locomotion’) just a special case of motion. Kuhn realized that these sorts of conceptual differences indicated breaks between different modes of thought, and he suspected that such breaks must be significant both for the nature of knowledge, and for the sense in which the development of knowledge can be said to make progress. Having made this discovery, Kuhn changed his career plans, leaving theoretical physics to pursue this strange phenomenon(Oberheim 2013).
This is precisely the sort of semantic incommensurability mentioned before. Some referents to which 'motion' had previously had reference, they no longer did according to the contemporary scientific paradigm.
As we mentioned before, Kuhn was not the first thinker to develop the notion of scientific incommensurability. Though he did contribute dramatically to the development of the sociology of natural sciences, the bacteriologist Ludwik Fleck composed a work called "Genesis and Development of a Scientific Fact." Fleck used the same word as Kuhn to describe scientific disciplines which examined totally different phenomena. Like Kuhn, Fleck denied that we could think of science as so linear and progressive a development of knowledge or path towards the truth, as science is naively thought of in many popular circles today.
Indeed, Fleck anticipated many of Kuhn's insights, even including his influence by Gestalt psychology:
Fleck emphasized that scientific terms acquire their meanings through their application within a particular theoretical context and that those meanings change when theories change in the course of advance, even offering the example of ‘chemical elements’ and ‘compounds’ repeated by Kuhn (Fleck 1979 , 25, 39, 40, 53–54). Fleck emphasized the theory-ladenness of observation with explicit reference to Gestalt switches; stressing that a ‘thought-style’ determines not only the meanings of the concepts it uses, but also the perception of phenomena to be explained, developing examples from the history of anatomical representation (1979 , 66; 1986 ). Fleck (like Kuhn, Feyerabend and Wittgenstein) acknowledged Wolfgang Köhler's work in psychology of perception in this regard. Fleck concluded that scientific advance is not cumulative, that conceptual differences between members of different scientific communities cause communication difficulties between them (1979 , 109), and later for historians trying to understand older ideas (1979 , 83–85, 89). Fleck even emphasized that meaning change in the course of scientific advance causes translation failure between theories, anticipating a central aspect of Kuhn's later notion of taxonomic incommensurability (e.g. 1986 , 83). While Fleck is often celebrated as an influential figure in the development of sociology of science, recent research has been highly critical of Fleck's shoddy scientific research and dubious experimental practices that include experimentation on humans involving obvious ethical violations (Hedfors 2007a; 2007b) (Oberheim 2013).
It is to Gestalt psychology that we will now turn. Wolfgang Köhler emphasized the importance of conceiving of perception as a "Gestalt" or organized whole, rather than merely a discrete set of objects. Thus, we see a psychological holism in his psychology that is in obvious continuity with the semantic, conceptual and methodological holism of Fleck and Kuhn. Interestingly enough, Köhler wanted to limit this Gestalt notion to psychology because he believed that if we were to predicate such a quality of the scientific discipline, their precision would be compromised. Yet this is exactly what Kuhn proposes we do.
There is controversy over the extent to which Kuhn's understanding of theoretical incommensurability changed and developed over the years. Some tend to emphasize a radical shift in Kuhn's thinking on the subject, while others argue that such a shift is oftentimes overstated. Let's look in detail at two of the major understandings of commensurability in Kuhn's thought. They are:
1) Taxonomic incommensurability - this refers to how certain scientific discoveries radically contradict the conception of the world held by a chronologically antecedent scientific discovery, such as Newton's distinctive contributions to physics (Oberheim 2013). Such incommensurability occurs when a phenomenon is classified within the context of a distinct scientific paradigm in such a way that it could not be straightforwardly translated into a category within another scientific paradigm:
For example, Ptolemy's theory classifies the sun as a planet, where planets orbit the earth, while Copernicus' theory classifies the sun as a star, where planets orbit stars like the sun. A correct statement according to Copernican theory, such as “Planets orbit the sun” is incoherent in Ptolemaic vocabulary (2000 , 94). Moreover, the Copernican claim that the planets orbit the sun could not even have been made without abandoning the Ptolemaic concepts and developing new ones to replace (and not supplement) them(Oberheim 2013)
More interesting yet, Kuhn argued that scientific revolutions produce groups of heterogeneous yet contemporaneous scientific sub-disciplines which classify the same set of objects in a totally different manner, according to different principles and laws.
Kuhn no longer represents scientific advance as a linear progression from pre-normal science to normal science, through crisis to revolution that results in a new phase of normal science. Instead, scientific revolutions are compared to the process of speciation in biology, in that they result in branching into sub-disciplines that resemble a phylogenetic tree. The application of the relation of incommensurability is no longer restricted to diachronic episodes of scientific advance in which two theories are separated by a revolution. The contemporaneous sub-disciplines that result from a scientific revolution can also be incommensurable with each other. The incommensurability derives from different training required to master the incompatible kind terms used to state their laws and theories. These shared kind terms cross-classify the same set of objects into different sets of kinds, resulting in mutually exclusive lexical taxonomies that break the no-overlap principle. Moreover, now not only are both processes (scientific progress and biological evolution) similar in that they are not fixed in advance on some set goal (i.e. truth), but driven from behind (i.e. away from anomalies that play an analogous role to selection pressure), but also the incommensurability of scientific theories is presented as analogous to the isolating mechanisms required for speciation (Kuhn 2000 , 94–99) (Oberheim 2013)
It is at this point that Kuhn's understanding of taxonomic incommensurability becomes astonishingly similar to Van Til's understanding of worldview incommensurability, according to which utterances only ever take place within, and presuppose, a specific worldview. Kuhn argued that each lexical taxonomy creates a distinct realm in which propositions can be declared true or false according to its own distinct standards of rationality. Each set of standards of rationality constitutes what a Christian presuppositionalist would refer to as a 'worldview', which is roughly what Kuhn means when he refers to lexical taxonomies.
Kuhn compared the function of such lexical taxonomies to Kant's a priori when taken in a relativized sense. Each lexicon makes a corresponding form of life possible within which the truth or falsity of propositions may be both claimed and rationally justified. For example, with the Aristotelian lexicon, one can speak of the truth or falsity of Aristotelian assertions, but these truth values have no bearing on the truth of apparently similar assertions made with the Newtonian lexicon (Kuhn 2000 , 244). A lexicon is thus constitutive of the objects of knowledge (Kuhn 2000 , 245); and consequently, Kuhn rejected characterizations of scientific progress according to which science zeros in on the truth...Instead, the logical status of a lexical structure, like that of word-meanings in general, is that of convention, and the justification of a lexicon or of lexical change can only be pragmatic (2000 , 244). Kuhn thus reaffirmed his earlier claim that the notion of a match or correspondence between the ontology of a theory and its real counterpart in nature is illusive in principle (1970, 206; 2000 , 244). The implications that incommensurability has for scientific realism have been widely discussed and continue to be controversial (cf. Devitt 2001, Oberheim and Hoyningen-Huene 1997, Sankey 2009) (Oberheim 2013)
It is Kuhn's reference to Kant that is perhaps particularly instructive for the Van Tillian response. Kuhn understands that all scientists operate according to definitive presuppositions which are not themselves scientifically determined, but which constitute alogical first principles. Van Til dedicates a great deal of his work to developing the importance of understanding the notion of an intellectual first principle by which we conceive of and interpret the world. Indeed, Van Til himself was largely inspired by Kant in this respect. However, for Van Til, the inspiration was drawn not from Kant's notion of the a priori, as it was from Kant's notion of a transcendental argument; a concept we will discuss more in detail later on. His semantic and doxastic holism is likewise quite similar to Wittgenstein's belief that reality is linguistically constructed, and that utterances do not so much refer to reality as they function as components in a holistic worldview-system. So Oberheim (2013):
A lexicon is not only prerequisite to making meaningful statements, it also sets limits on what can be meaningfully said within the community of speakers that share it: “There is, for example, no way, even in an enriched Newtonian vocabulary, to convey the Aristotelian propositions regularly misconstrued as asserting the proportionality of force and motion or the impossibility of a void. Using our conceptual lexicon, these Aristotelian propositions cannot be expressed — they are simply ineffable — and we are barred by the no-overlap principle from access to the concepts required to express them ”
Kuhn's later notion of the incommensurability of scientific theories is based on effability. The structure of the lexicon shared by a particular community determines how the world can be described by its members, as well as how they will misunderstand the history of their own discipline; that is, unless they learn to understand older terms according to the structure of the older lexicon. Where Kuhn had earlier likened the process by which historians come to understand antiquated science as a special type of translation, he retracted these claims, insisting that the process is one of language learning, not translation(Oberheim 2013)
2) Methodological incommensurability - Next, let us look at methodological incommensurability. This is the form of commensurability which we mentioned before, according to which there is no objective, monolithic standard by which we can determine what counts as good science and what counts as bad science. This has recently been referred to as "Kuhn-underdetermination" and it is the point that there is no clear, definite standard by which we can adjudicate between competing scientific theories.
"The basic idea was developed out of Kuhn and Feyerabend's rejections of the traditional view that a distinguishing feature of science is a uniform, invariant scientific method, that remains fixed throughout its development...Feyerabend famously argued that every proposed methodological rule has been fruitfully violated at some point in the course of scientific advance, and that only by breaking such rules could scientists have made the progressive steps for which they are praised...He concluded that the idea of a fixed, historically invariant scientific method is a myth. There are no universally applicable methodological rules. The only methodological rule that is universally applicable is ‘anything goes’, which buys its universality at the cost of being completely empty"(Oberheim 2013)
Kuhn compared the notion of a scientific method to that of a political revolution constituted primarily by shared consent of groups of individuals, guided by loosely defined sets of epistemic values, rather than a clearly defined, objective method (Oberheim 2013). We can never have recourse to a straightforward formula or algorithm in our scientific investigation. "Different scientists apply these values differently, and they may even pull in different directions, so that there may be rational disagreement between scientists from incommensurable paradigms, who support different theories due to their weighing the same values differently"(Oberheim 2013).
As mentioned earlier, Kuhn's understanding of the incommensurability of scientific theories from distinct paradigms is quite similar to the epistemological insights of Paul Feyerabend. The latter dedicated his work to attacking the notion of "conceptual conservatism," which is understood as the tendency to favor the existing state of philosophical affairs rather than opting for potential improvement by replacing our current concepts with other more useful ones (Oberheim 2013). This philosophy was pitted quite explicitly against the philosophy of science advocated by the logical positivists which we have detailed before. Indeed, even relatively open-minded philosophers like Popper and Kuhn were not exempt from being targets of this critique. "Feyerabend argued that all of these views cannot accommodate the fact that the history of science reveals revolutionary developments in which incommensurable alternatives replaced existing ideas in the course of progress"(Oberheim 2013).
Feyerabend used the concept of incommensurability in order to argue against Nagel's "theory of reduction" and "the Hempel-Oppenheim theory of explanation"(Oberheim 2013). Feyerabend limited this concept to theories which purported to describe every object in the universe (Oberheim 2013). It was successive instances of these which Feyerabend insisted were incommensurable with one another. Feyerabend's understanding of the incommensurability of scientific theories is very similar to that of Van Til's understanding of the incommensurability of worldviews:
By limiting incommensurability to universal theories, Feyerabend meant only those that apply to all objects in the universe. By limiting incommensurability to fundamental theories, Feyerabend meant those that have ontological implications; i.e., those that have implications about the very nature of reality. Universal, fundamental scientific theories can be incommensurable only if they are interpreted realistically, according to Feyerabend, because otherwise they cannot compete as the one true theory, and are thus not mutually exclusive. By calling two such theories incommensurable, Feyerabend meant that they were conceptually incompatible: The main concepts of one could neither be defined on the basis of the primitive descriptive terms of the other, nor related to them via a correct empirical statement (1962, 74, 90). As a consequence, it is impossible to reduce incommensurable theories formally
Concepts are incommensurable, according to Feyerabend, because they belong to mutually exclusive theoretical perspectives. These perspectives are mutually exclusive because they give incompatible accounts of the nature of reality. Feyerabend argued that because the meanings of their terms are provided by the theories to which they belong, when there is theoretical change, there are meaning changes (1962, 68, 94). Feyerabend argued that these changes in meaning affect our theoretical and observational terms, as well as our conception of the nature of reality. When this occurs, there is incommensurability; or as Feyerabend later characterized his view: “a theory is incommensurable with another if its ontological consequences are incompatible with the ontological consequences of the latter” (1981a, xi). The idea is intended to capture conceptual incompatibility due to changes of meaning that occur in theoretical transitions that affect our ontological beliefs. Two fundamental theories are incommensurable because the meanings of their terms are determined by the theoretical principles that govern their use, and these principles are qualitatively incompatible (1962, 58) (Oberheim 2013)
Such worldview-incommensurability is astonishingly similar to the worldview-incommensurability of Cornelius Van Til:
True human knowledge corresponds to the knowledge which God has of himself and his world. Suppose that I am a scientist investigating the life and ways of a cow. What is this cow? I say it is an animal. But that only pushes the question back. What is an animal? To answer that question I must know what life is. But again, to know what life is I must know how it is related to the inorganic world. And so I may and must continue till I reach the borders of the universe. And even when I have reached the borders of the universe, I do not yet know what the cow is. Complete knowledge of what a cow is call be had only by an absolute intelligence, i.e., by one who has, so to speak, the blueprint of the whole universe. But it does not follow from this that the knowledge of the cow that I have is not true as far as it goes. It is true if it corresponds to the knowledge that God has of the cow(Van Til, "A Survey of Christian Epistemology")
Thus, what the Christian means by 'cow' is something radically different from what the unbeliever means by 'cow.' The reason for this is that each person examines the cow from a totally different theoretical perspective, and the reason such a totally different theoretical perspective is operative is because each theoretical perspective takes its cue from a totally different worldview. Kuhn might say that what the Christian means by 'cow' is as radically different from what the non-Christian means when he refers to a 'cow' as Aristotle's use of the concept of 'motion' was from Newton's. Thus Van Til:
Starting the argument from the other direction, we can say that the method of reasoning employed by Plato involves an independence on the part of man in order to have any meaning at all. Plato had to assume the underived character of the human mind in order to assume the underived character of the whole of the temporal universe. It really makes very little difference in this connection whether one begins with metaphysics and ends with epistemology, or whether one begins with epistemology and ends with metaphysics. The important thing to observe is that the one is involved in the other. The assumed independence of the universe as a whole leads to, and implies, an original independence on the part of the mind of man. On the other hand, the assumed independence of the human mind leads to and implies an original independence of the universe(Van Til)
Van Til's worldview-holism, at least with respect to the notion that there is no such thing as purely neutral reasoning, is therefore quite at home with the holism of Feyerabend and Kuhn. The point is thus: When men like Bill Nye attempt to problematize the Christian view of creation, we can point to these points as ones which have historically been taken seriously within the philosophy of science. Presuppositionalists are not engaging in desperate subterfuge when we point out that all interpretation of evidence is conditioned by worldviews. On the contrary, this is an important and legitimate point to make.
Indeed, one of Feyerabend's crucial points is that historic empiricists are no less dogmatics than the rationalists from whose thought they had attempted to distance themselves (Oberheim 2013). He denies that the terms which empiricists have historically used in developing their epistemologies "remain stable through theoretical transitions; or what Feyerabend called the principle of meaning invariance(Oberheim 2013). Feyerabend makes the point that a scientific theory can be incommensurable with another if the two cannot be brought into logical relation. We can never formally deduce special or general relativity from Newtonian mechanics. Furthermore, Feyerabend sees the revision of one's scientific conception of the world as entailing a radical rejection of the beliefs and theories of the antecedent scientific paradigm, which is a tacit admission that their beliefs are not true. Since such radical revision is characteristic of scientific paradigm shifts, it follows that scientific investigation can never be thought of as consisting of substantive advance of knowledge. Thus:
Feyerabend developed ‘thesis I’, according to which the interpretation of an observation language is determined by the theories that we use to explain what we observe, and it changes as soon as those theories change (1958a, 163). Feyerabend proceeded to argue that when older theories are replaced, the meanings of the observational terms used to test the theories change. Just as in (1962), the result is incommensurability: The idea that successive scientific theories are conceptually incompatible and consequently logically disjoint. Feyerabend's ‘thesis I’ is thus an early version of his incommensurability thesis. In his (1958a), with this notion of incommensurability, Feyerabend challenged an implicit conceptual conservativism in logical positivism: The assumption that theoretical terms derive their meaning solely through their connection with experience, and that experience itself is a stable (or unchanging) foundation on which theoretical meaning can be based. Instead of such a bottom-up version of the relation of experience and theoretical knowledge, according to which experience determines the meanings of our theoretical terms, Feyerabend argued for a top-down version, according to which our theories determine the meaning we attach to our experiences. According to Feyerabend, experience cannot be taken for granted as some kind of fixed, neutral basis for comparing theories. Rather, it takes on its particular character in light of the theories we bring to it. An investigation of the source of these ideas reveals the founding father of the notion of incommensurability in the contemporary history and philosophy of science (Oberheim 2013)
Oberheim, Eric and Hoyningen-Huene, Paul, "The Incommensurability of Scientific Theories", The Stanford Encyclopedia of Philosophy (Spring 2013 Edition), Edward N. Zalta (ed.), URL = <plato.stanford.edu/archives/spr2013/entries/incommensurability/>.