This is a nice summary of Kuhn’s ideas from his SSR (with some really great examples). Your main question (where is in all this objectivity and how to get rid of relativism?) puzzled both Kuhn as well as the post-Kuhnian philosophers of science. In his later work (The Road Since Structure) Kuhn tried to answer these questions in more detail, leaning towards a Kantian interpretation of the world (roughly: even though we do not have an access to the world as such, the world does give a “resistance” to our attempts at forming knowledge about it, which is why not anything goes; a good guide for this is Paul Hoyningen-Huene’s excellent book on Kuhn “Reconstructing scientific revolutions: Thomas S. Kuhn’s philosophy of science”).
I don’t know enough about predictive coding to comment on that comparison, but here are two comments on some of the above issues:
1) While the shift from one paradigm to another often appears to be a matter of “mob psychology” (as Lakatos put it), Kuhn actually discusses elsewhere the process of ‘persuasion’ and ‘translation’ that the proponents of rivaling paradigm can employ. Even though scientists may belong to mutually incommensurable paradigms, the ‘communication breakdown’ can be avoided via these processes (for more on this see this, also available here).
2) Concerning the objectivity of the world, the reason why this issue is not so simple for Kuhn is that he rejects the idea of the “mind-independent world”. This point is often misunderstood and either ignored or placed under Kuhn’s ‘obscure ideas’ mainly because in his attempts to explicate it, Kuhn gets very close to the so-called continental philosophical style, which sometimes irks the shit out of analytically-minded philosophers ;) The following passage from a discussion on Kuhn may not make things much clearer without an additional context, but it points to the relevant parts of Kuhn’s work on this and it hopefully shows why Kuhn doesn’t accept a simple dichotomy between the mind-dependent and mind-independent world (bold emphasis added):
[According to Kuhn]
.. truth cannot be anything like correspondence to reality. I am not suggesting, let me emphasize, that there is a reality which science fails to get at. My point is rather that no sense can be made of the notion of reality as it has ordinarily functioned in philosophy of science. (Kuhn, 2000, p. 115)
Kuhn thus argues not only that the match between the mind and the reality that is independent from it is not assessable, but that this match is nonsensical.
But the natural sciences, dealing objectively with the real world (as they do), are generally held to be immune. Their truths (and falsities) are thought to transcend the ravages of temporal, cultural, and linguistic change. I am suggesting, of course, that they cannot do so. Neither the descriptive nor the theoretical language of natural science provides the bedrock such transcendence would require. (Ibid., p. 75)
The reasons for these claims need to be explicated in view of Kuhn’s discussion of the notion of world. First of all, Kuhn emphasizes the world-constitutive role of intentionality and mental representations (p. 103), of a lexicon that is always already in place (p. 86):
different languages impose different structures on the world . . . where the structure is different, the world is different. (Ibid., p. 52) The world itself must be somehow lexicon-dependent. (Ibid., p. 77)
What is thus at stake is the notion of a mind-independent, or, in Putnam’s terms, ‘ready-made’ world. And for the reasons given above, this term is, for Kuhn, nonsensical. Nevertheless, he warns his readers that this does not imply that the world is somehow mind-dependent: ‘the metaphor of a mind-dependent world—like its cousin, the constructed or invented world—proves to be deeply misleading’ (ibid., p. 103).
How should the notion of world be treated then? Instead of the strict dichotomy between the mind-independent world and our representations of it, Kuhn proposes ‘a sort of post-Darwinian Kantianism. Like the Kantian categories, the lexicon supplies pre-conditions of possible experience’ (ibid., p. 104). And as the lexical categories change, both in a diachronous and a synchronous manner, ‘the world . . . alters with time and from one community to the next’ (ibid., p. 102). Kuhn compares a permanent, fixed, and stable foundation ‘underlying all these processes of differentiation and change’ to ‘Kant’s Ding an sich’, which ‘is ineffable, undescribable, undiscussable’ (ibid., p. 104). And what replaces the dichotomy of mind–language–thinking and the one big mind-independent world (ibid., p. 120) is the concept of ‘niche’: ‘the world is our representation of our niche’ (ibid., p. 103).
Those niches, which both create and are created by the conceptual and instrumental tools with which their inhabitants practice upon them, are as solid, real, resistant to arbitrary change as the external world was once said to be. (Ibid., p. 120)
Now, what has become of the notion of truth in Kuhn’s post-Darwinian Kantianism? Truth can at best be seen as having ‘only intra-theoretic applications’ (Kuhn, 1970, p. 266): ‘Evaluation of a statement’s truth values is, in short, an activity that can be conducted only with a lexicon already in place’ (Kuhn, 2000, p. 77). By contrast, ‘The ways of being-in-the-world which a lexicon provides are not candidates for true/false’ (ibid., p. 104). None of these ‘form[s] of life’, ‘practice[s]-in-the-world’ gives ‘privileged access to a real, as against an invented, world’ (ibid., pp. 103–104). Therefore the speech of theories becoming truer ‘has a vaguely ungrammatical ring: it is hard to know quite what those who use it have in mind’ (ibid., p. 115). Furthermore, if with Kuhn the sciences form a ‘complex but unsystematic structure of distinct specialties or species’ and therefore have to be ‘viewed as plural’ (ibid., p. 119), and if the niches ‘do not sum to a single coherent whole of which we and the practitioners of all the individual scientific specialties are inhabitants’ (ibid., p. 120), then ‘there is no basis for talk of science’s gradual elimination of all worlds excepting the single real one’ (ibid., p. 86).
This sums up some parts of late Kuhn’s thoughts on the growth of knowledge and its non-additive character. Now, one can ask: but what does this practically mean? What kind of methodological guidelines does this give us? And this is where issues are perhaps not so surprising (or disturbing). I think the most important points here are:
1) a complex defeasible character of scientific models and theories (complex in the sense that falsifying a theory may not be a matter of deciding in view of one or two experiments, as discussed in the article; instead Kuhn speaks of the importance of ‘epistemic values’, such as scope, adequacy, simplicity, consistency, fruitfulness—which guide scientists to prefer one theory over another, and which at the end of the day lead the community to replace one paradigm with another; this is closely related to the next point);
2) instead of assessing the truthfulness of scientific knowledge, post-Kuhnian philosophers of science prefer to speak of the assessment of their performance in terms of epistemic (or as sometimes called ‘cognitive’) values, based on empirical evidence (in other words, scientists are considered as accepting a theory not because it is ‘true’ or ‘truth-like’ but because it scores highly with respect to its predictive accuracy, explanatory scope, etc.
3) the presence of conceptual frameworks underlying scientific theories, which complicate their unification and integration (and which have inspired a whole range of accounts proposing ‘scientific pluralism’), and which may also give rise to rational disagreements in science, make the learning and communication across paradigms cumbersome, etc.
This is a nice summary of Kuhn’s ideas from his SSR (with some really great examples). Your main question (where is in all this objectivity and how to get rid of relativism?) puzzled both Kuhn as well as the post-Kuhnian philosophers of science. In his later work (The Road Since Structure) Kuhn tried to answer these questions in more detail, leaning towards a Kantian interpretation of the world (roughly: even though we do not have an access to the world as such, the world does give a “resistance” to our attempts at forming knowledge about it, which is why not anything goes; a good guide for this is Paul Hoyningen-Huene’s excellent book on Kuhn “Reconstructing scientific revolutions: Thomas S. Kuhn’s philosophy of science”).
I don’t know enough about predictive coding to comment on that comparison, but here are two comments on some of the above issues:
1) While the shift from one paradigm to another often appears to be a matter of “mob psychology” (as Lakatos put it), Kuhn actually discusses elsewhere the process of ‘persuasion’ and ‘translation’ that the proponents of rivaling paradigm can employ. Even though scientists may belong to mutually incommensurable paradigms, the ‘communication breakdown’ can be avoided via these processes (for more on this see this, also available here).
2) Concerning the objectivity of the world, the reason why this issue is not so simple for Kuhn is that he rejects the idea of the “mind-independent world”. This point is often misunderstood and either ignored or placed under Kuhn’s ‘obscure ideas’ mainly because in his attempts to explicate it, Kuhn gets very close to the so-called continental philosophical style, which sometimes irks the shit out of analytically-minded philosophers ;) The following passage from a discussion on Kuhn may not make things much clearer without an additional context, but it points to the relevant parts of Kuhn’s work on this and it hopefully shows why Kuhn doesn’t accept a simple dichotomy between the mind-dependent and mind-independent world (bold emphasis added):
This sums up some parts of late Kuhn’s thoughts on the growth of knowledge and its non-additive character. Now, one can ask: but what does this practically mean? What kind of methodological guidelines does this give us? And this is where issues are perhaps not so surprising (or disturbing). I think the most important points here are:
1) a complex defeasible character of scientific models and theories (complex in the sense that falsifying a theory may not be a matter of deciding in view of one or two experiments, as discussed in the article; instead Kuhn speaks of the importance of ‘epistemic values’, such as scope, adequacy, simplicity, consistency, fruitfulness—which guide scientists to prefer one theory over another, and which at the end of the day lead the community to replace one paradigm with another; this is closely related to the next point);
2) instead of assessing the truthfulness of scientific knowledge, post-Kuhnian philosophers of science prefer to speak of the assessment of their performance in terms of epistemic (or as sometimes called ‘cognitive’) values, based on empirical evidence (in other words, scientists are considered as accepting a theory not because it is ‘true’ or ‘truth-like’ but because it scores highly with respect to its predictive accuracy, explanatory scope, etc.
3) the presence of conceptual frameworks underlying scientific theories, which complicate their unification and integration (and which have inspired a whole range of accounts proposing ‘scientific pluralism’), and which may also give rise to rational disagreements in science, make the learning and communication across paradigms cumbersome, etc.