Tag Archives: Massimo Pigliucci

Scientism: Part 4: Reductionism

This is the Fourth Part of a review of Science Unlimited? The Challenges of Scientism, edited by Maarten Boudry and Massimo Pigliucci. See also Part 1: Pseudoscience, Part 2: The Humanities, and Part 3: Philosophy.

Reductionism is a big, bad, bogey word, usually uttered by those accusing others of holding naive and simplistic notions. The dominant opinion among philosophers is that reductionism does not work, whereas scientists use reductionist methods all the time and see nothing wrong with doing so.

That paradox is resolved by realising that “reductionism” means very different things to different people. To scientists it is an ontological thesis. It says that if one exactly replicates all the low-level ontology of a complex system, then all of the high-level behaviour would be entailed. Thus there cannot be a difference in high-level behaviour without there being a low-level difference (if someone is thinking “I fancy coffee” instead of “I fancy tea”, then there must be a difference in patterns of electrical signals swirling around their neurons).

To philosophers, however, “reductionism” is about explanations and theories. It asserts something along the lines that high-level explanations can always be translated into low-level explanations, and that the low-level explanations are more important or more proper, and that ideally the high-level explanations could be dispensed with. I say “something along the lines” because this sort of eliminative reductionism is pretty much a strawman in that no-one (sensible) advocates it. And philosophers are right, in general it does not work.

But the scientific notion of ontological reductionism does work. At least, all of science assumes that thesis, and science works very well, producing unarguable and unmatched mastery of technology and engineering. Since adopting that thesis works so well we can be pretty sure that ontological reductionism (which philosophers may instead refer to as “supervenience physicalism”) is a true feature of the real world.

But the different meanings lead to miscommunication. “Scientism” is supposed to include a naive faith in reductionism, which the accuser would take to be the philosophers’ inter-theoretic reductionism. But those defending scientism are likely to think like scientists, and so hold only to ontological reductionism but not defend ideas of inter-theoretic reductionism. The latter might work in limited instances, but does not work in general.

Most physicists would agree. In his Reductionism Redux essay, Stephen Weinberg refers to inter-theoretic reductionism as “petty” reductionism, saying that it usually doesn’t work, while he regards ontological reductionism as a “grand” reductionism that underpins all of science. Similarly Sean Carroll defines reductionism as the idea that “objects are completely defined by the states of their components”, and says: “I could imagine hypothetical worlds in which reductionism failed … It’s just not our world”.

Carroll also says that one can “object to the claim that ‘the best way to understand complex systems is to analyze their component parts, ignoring higher-level structures’, but only if you can find someone who actually makes that claim”, and adds that: “nobody thinks that the right approach is to break a giraffe down to quarks and leptons and start cranking out the Feynman diagrams”.

So let’s see what the philosophers in Boudry and Pigliucci’s book make of the concept. Filip Buekens accepts Alex Rosenberg’s claim that “physics fixes all the facts” (by which Rosenberg means the supervenience thesis that the state of a complex system is completely specified if all its low-level physical properties are specified), but he demurs about the “much stronger claim” that “all other facts are ultimately explained by physics”.

He continues: “conceptual anti-reductionism holds that explanations employing psychological concepts cannot be replaced by explanatory strategies relying on physical concepts”. So one could not translate the concept “fear” into language about electrons and protons and their motions.

He’s right on the latter point, but it’s important to realise that explanations are not mutually exclusive. Explanations are always commentaries about some aspect of a system. They never describe the entirety of a system. And that means that multiple different explanations can be true at the same time.

The doctrine of supervenience says that one could — given an advanced Star Trek transporter device — exactly replicate a system from an exhaustive listing of every particle it contains (and the replicated system would manifest the same high-level properties including “fear”). But an “explanation”, being a commentary about aspects of a system, never contains enough information to do this. You could not feed “Tom was afraid of the dog” into the transporter and exactly replicate Tom and the dog from that alone.

The same holds for explanations used in physics. They also are reduced-information commentaries; physicists no more work with exhaustive listings of particles than psychologists do — they are too unwieldly and so impractical as to be useless. Thus, even in physics there are multiple higher-level concepts (such as “temperature”, “entropy”, “elasticity”, “ductility”, “conductivity”) that are properties of an ensemble, and which are not even defined at the lower level of single particles.

Since, for any system, there will always be many mutually-consistent and equally-true explanations, it follows that even if one develops explanations of high-level properties in terms of lower-level properties, these will never replace and do-away with high-level explanations, they will only add to and complement them.

Richard Feynman said that any good theoretical physicist knows six different ways of thinking about the same thing. Explanations at different levels of description are complementary ways of thinking about the same thing. They don’t replace or abolish other explanations, instead they must all be simultaneously true. And the different explanations are held together, coherently, not by the philosophers’ notion of inter-theoretical reductionism — not by translations between different explanations — but by the doctrine of ontological reductionism or supervenience.

As an aside here, philosophers use the weird term “special science” for sciences where inter-theoretic reductionism is held not to work, and by doing that they imply that it does work for at least some sciences, by which they usually mean physics or perhaps fundamental physics; they are wrong, it does not work even there, there are no “special” sciences since they are all “special”.

I can’t help thinking that much philosophical travail against inter-theoretic reductionism is misplaced, in the sense of attacking doctrines that no-one holds. Stephen Pinker’s essay on the humanities aroused fears of a hostile take over that reduces the humanities to a mere adjunct of science. But, as Russell Blackford explains in his contribution to the volume, that is a mis-reading of Pinker, who is instead arguing for a consilience in which different styles of approach complement each other.

Similarly, Taner Edis expounds a scientism that “highlights continuities in the various ways we produce knowledge, and weaves the products of our knowledge-seeking enterprises into a naturalistic overall picture”, saying that: “this scientism is harmless: it seeks connections and coherence, not intellectual conquest”.

The most direct condemnation of reductionism in the book is by Mariam Thalos. Declaring reductionism “the enemy”, she argues against sociobiology and the claim that, because human brains have evolved “therefore biology explains human behaviour too, utilizing principles of natural selection”. But that’s true, it does!

Thalos, however, suggests that accepting this idea “would with one stroke sweep away all competing models of human behaviour”. Interpreting that narrowly, yes it would sweep away competing models — those that are incompatible with the sociobiology perspective. But it would not sweep away complementary models and explanations — those that are different from but compatible with the evolutionary perspective, and which are equally true.

Thalos generalises her argument: physics explains the behaviour of physical bodies, humans are made of physical stuff, therefore physics explains human behaviour. “Whence, biology, as such, is made irrelevant.”

To this she adds that if we accept that “physics explains human behaviour, utilizing physical principles”, then “we are explicitly denying the need for biological theory as independently valuable in the enterprise of scientific explanation”. Thus, to Thalos, only one type of explanation can be valid. Physical systems can only be explained in physical terms; biological systems can only be explained in biological terms.

No! This is a rejection of the “grand reductionism” that is the very soul of science. Complex systems (such as humans) need explanations at all levels of analysis. We should develop explanations of humans in physical terms, and in chemical terms, and in bio-chemical terms, and in biological terms, and in evolutionary terms, and in psychological terms, and in sociological terms, and in the languages of the humanities. All such explanations complement each other and mesh into a grand, consilient picture. The different explanations don’t compete with or displace each other, they complement each other. They must all be mutually compatible and mutually build to an overall grand picture in which they are all true.

That follows from the doctrine of scientific or ontological reductionism, which holds everything together because it tells us that all these different explanations are about the same ontological stuff; they are reporting different aspects of the same ensemble. And that is the consilient grand picture of science and of scientism.

This is not a merely philosophical point, it is eminently practical. Given multiple explanations about the same stuff, we then need to ensure that they are fully compatibile, and investigating that is the central driving force of science. Ensuring that the explanations in physical terms mesh seamlessly with the explanations in chemical terms, and with the bio-chemical explanations, the biological explanations, and the evolutionary and psychological explanations, is exactly how science makes progress.

Any field that wants to stand aside from that process risks turning itself into a parochial fiefdom prey to fads and ideologies (a current example being areas of sociology that totally ignore the genetic underpinnings of human behaviour), and deprives itself of the best tool that science has.

Science Unlimited, Part Three: Philosophy

This is the Third Part of a review of Science Unlimited? The Challenges of Scientism, edited by Maarten Boudry and Massimo Pigliucci. See also Part 1, focusing on pseudoscience, and Part 2, focusing on the humanities.

Science started out as “natural philosophy” until Whewell coined the newer name “science”. As a scientist I have a PhD and am thus a “Doctor of Philosophy”. And yet many philosophers assert that today “philosophy” is an enterprise that is distinct from “science”.

The argument runs that philosophy is about exploration of concepts, and what can be deduced purely by thinking about concepts, whereas science is heavily empirical, rooted in observation of the world. Thus philosophy (exploration of concepts) and science (empirical observation) are fundamentally different beasts. And both are necessary for a proper understanding.

But, for this distinction to hold, a necessary corrollary is that science does not involve exploration of concepts, and concerns itself only with the accumulation of observation. Yet to me that is an utterly impoverished view of science, and one that is untenable. In order to advance understanding we need both the exploration of concepts and the guidance of empirical observation — either on its own won’t get far. Accumulating observations by itself is mere “stamp collecting” (to quote a derogatory remark that physicists aim at anyone not paying sufficient attention to explanations and understanding). As philosophers themselves know, all observation is “theory laden” in that one cannot even assimilate observational evidence without equal attention to what it means.

In essence, science is a continual process of revising and improving a “web of ideas” that contains our understanding of the world. We continually test the web by comparing its outputs to empirical data, looking for any mismatch, and then trying to figure out the best way of adjusting the web in order to eliminate the anomaly. It follows that attention to the internal coherence of the web of ideas, and exploring the implications of the ideas — and thus analysis of concepts — is a vital and basic part of the overall scientific enterprise.

The two halves of the whole are perhaps most clearly seen in physics, where practitioners are divided into “theoretical physicists”, who spend their lives exploring the implications of ideas and trying to scheme up better ones, and “observers” and “experimentalists” who concentrate on adding to the pile of empirical data that tests the concepts. Obviously this only works if the two halves are continually talking to each other, and so everyone sees themselves as part of the same overall enterprise, specialising in one “style” of science because division of labour allows the focused expertise necessary to make progress.

To me as a physicist, it makes little sense to read that some philosophers think that exploring ideas and concepts for their own sake is a philosophical activity that is “not science” and is clearly distinct from science. So why is it then defended by some philosophers? I suggest that the reason is sociological. Science nowadays is such a juggernaut that adjacent disciplines fear being trampled underfoot, and so jostle to establish a bailiwick of their own from which science is excluded. While understandable, such a path could lead to irrelevance.

Philosophy, with its role of asking certain types of question, is better thought of, not as distinct from science, but as a style of doing science, in the broadest sense of “science” as increasing our understanding of the world. Other “styles” of science, in addition to theoretical analysis, include accumulating observations, designing and performing experiments, and modelling a situation on a computer. The best approach is to combine and synthesize all of these styles. None of them would get us far on its own, and they best succeed in harmony with the others. Philosophy, therefore, is best done in close conjunction with adjacent disciplines, such as the sciences, and could condemn itself to pointless meanderings if it forgets that.

As expected, the authors in Science Unlimited have a spread of views on this issue. Maarten Boudry is closest to my own view, arguing against those of his colleagues who “still regard philosophy as independent from and conceptually prior to science”, and saying instead that: “much of philosophy is now tightly ensnared in the web of knowledge. Philosophy of mind shades into cognitive science, neurology, and linguistics. Epistemology is intertwined with cognitive psychology and evolutionary biology”, while declaring — correctly — that the sciences “often deal with conceptual issues that can be characterized as broadly `philosophical’ in nature”.

Stephen Law, however, is less sympathetic to this view, saying: “philosophical questions are, for the most part, conceptual rather than scientific or empirical”, and that: “in order to solve many classic philosophical problems, we’ll need to retire to the armchair, not to the lab”.

But, equally, theoretical physicists don’t work with laboratory equipment, taking measurements, they work with ideas and concepts. The internal coherence of concepts about the world is just as much a concern for scientists as for philosophers.

A current example is the black-hole information paradox, where the paradox is that current models of black holes suggest that “information” (which itself is a highly abstract concept, not a direct observable) is destroyed when material falls into a black hole. And yet, a basic principle of quantum mechanics (the best theory of matter, thought to apply everywhere) says that information can never be destroyed. Trying to resolve the inconsistency is currently exercising many of the world’s top theoretical physicists, partly because the solution might point the way to a model of “quantum gravity”, the long-sought unification of quantum mechanics with general relativity. Yet this activity is entirely conceptual, since observations and experiments pertaining directly to the issue are way beyond current capabilities. Physicists still regard the enquiry as “scientific”, even if some philosophers might want to declare it to be “metaphysics”.

Stephen Law’s own example is Galileo’s thought experiment of dropping balls from the top of the Leaning Tower of Pisa. The thought experiment demonstrates that balls of different weights must fall at the same speed, else one arrives at a contradiction. Law asks: “Is Galileo’s thought experiment an example of science, or of philosophy?” Since it “targets a scientific theory”, about how physical objects behave, “perhaps it belongs more properly to science”, but, Law continues, “the same armchair method employed by Galileo is also regularly employed by philosophers”.

And just as often by scientists. And so both science and philosophy are about concepts, and there is no clear demarcation between them. Such a view is also advocated by Mariam Thalos, who writes: “I propose to use the label science for all of what Aristotle would have called knowledge. Hence it applies to anything that accepts the authority of a coherent set of standards that aim at truth. […] Thus, philosophy is a science”.

In contrast, Massimo Pigliucci attempts to draw clear distinctions between philosophy and science, boldly declaring:

I would go as far as to challenge my scientistically inclined colleagues who contributed to this volume to show me a single instance of systematic observation or experiment (i.e., an example of science) throughout this collection of essays. The contributions Maarten and I collected here are so inherently philosophical in nature that they stand as a self-evidence refuation that science is our only path to knowledge and understanding.

Here, Pigliucci explicitly limits science to: “systematic observation or experiment”, overlooking the entire conceptual, theoretical and model-building side of science. Yes, if you limit science to only that aspect, then that impoverished and neutered hemi-science would be inadequate on its own. You do indeed need all the different styles, working in concert, to do the best science, and that includes the conceptual analysis characteristic of Boudry & Pigliucci’s book of essays.

Pigliucci replies that such a broad conception of science amounts to: “redefining science in a way that is coextensive with reason itself, which is not only historically and factually grossly inaccurate but ultimately meaningless”.

But I deny that it is meaningless, instead it points to a consilience that is a necessary part of seeking out knowledge. None of the “styles” succeeds on its own. One cannot define science as being limited to “systematic observation or experiment” while excluding the conceptual and model-building side of science that is needed to interpret the observations and experiments; such a science would not function.

Philosophers themselves agree with this, pointing to the inevitably “theory-laden” nature of even simple observations. The Quinean-web view of science — with a constant iteration between observation and experiment, on the one hand, and a “web of ideas” on the other — demands that science be just as much about the “web of ideas” as about the observation and experiment. Thus I would go as far as suggesting that Pigliucci’s attempted demarcation between philosophy and science is not consistent with the nature of science and not consistent with the best philosophical understanding of science.

Part 4: Reductionism

Science Unlimited, Part Two: The Humanities

This is the Second Part of a review of “Science Unlimited? The Challenges of Scientism”, edited by Maarten Boudry and Massimo Pigliucci. Part 1, focusing on pseudoscience, is here.

The Claim of Scientism can be stated overly crudely as “science is the only way of answering questions”, which of course is guaranteed to raise hackles. But in the non-strawman version scientism does not assert that humanities can never contribute to knowledge, instead it asserts that ways of finding things out are fundamentally the same in all disciplines. Any differences in methods are then merely consequences of the types of evidence that are available, rather than reflecting an actual epistemological division into “different ways of knowing”. The prospect is not, therefore, of a hostile takeover of the humanities, but of a union or conscilience (to use a term that E. O. Wilson revived from Whewell).

In its least offensive statement, scientism states that science is pragmatic, and that it will use any type of evidence that it can get its hands on. Continue reading

Science Unlimited, Part One: Pseudoscience

Philosophers Maarten Boudry and Massimo Pigliucci have recently edited a volume of essays on the theme of scientism. The contributions to Science Unlimited? The Challenges of Scientism range from sympathetic to scientism to highly critical.

I’m aiming to write a series of blog posts reviewing the book, organised by major themes, though knowing me the “reviewing” task is likely to play second fiddle to arguing in favour of scientism.

Of course the term “scientism” was invented as a pejorative and so has been used with a range of meanings, many of them strawmen, but from the chapters of the book emerges a fairly coherent account of a “scientism” that many would adopt and defend.

This brand of scientism is a thesis about epistemology, asserting that the ways by which we find things out form a coherent and unified whole, and rejecting the idea that knowledge is divided into distinct domains, each with a different “way of knowing”. The best knowledge and understanding is produced by combining and synthesizing different approaches and disciplines, asserting that they must mesh seamlessly. Continue reading

On explanations and causality within physics

I recently watched a video by philosophers Massimo Pigliucci (City University of New York) and Daniel Kaufman (Missouri State University) discussing differences in styles of explanation between the natural sciences and the social sciences. There’s a lot in the video that I agree with, but I want to dissent on one issue. That is, I don’t agree that causality is as central to explanations within physics as the video suggests, and thus the differences with the social sciences are less pronounced than suggested. (Though, having said that, I do agree that there is one very big difference in that biological entities exhibit purpose and intention, whereas physical entities do not.)

Pigliucci and Kaufman suggest that “explanations” within the physical sciences are typically in terms of causation, and thus are of the form of pointing to antecedent causal events that are sufficient to explain subsequent events. They also discuss “laws of physics” as being “widely generalisable causal relations”.

I would instead say that physical laws are often not about causes and are just descriptive. They would thus be “widely generalisable descriptive relations”. The meaning of “explanation” within physics is also much broader than just causal explanations. More generally, “explanations” are linkages between descriptions of different aspects of the system. All systems, simple or complex, can be (partially) described in different ways, and if we show how those descriptions link together then we “explain”. Continue reading

On understanding, intuition, and Searle’s Chinese Room

You’ve just bought the latest in personal-assistant robots. You say to it: “Please put the dirty dishes in the dishwasher, then hoover the lounge, and then take the dog for a walk”. The robot is equipped with a microphone, speech-recognition software, and extensive programming on how to do tasks. It responds to your speech by doing exactly as requested, and ends up taking hold of the dog’s leash and setting off out of the house. All of this is well within current technological capability.

Did the robot understand the instructions?

Roughly half of people asked would answer, “yes of course it did, you’ve just said it did”, and be somewhat baffled by the question. The other half would reply along the lines of, “no, of course the robot did not understand, it was merely following a course determined by its programming and its sensory inputs; its microprocessor was simply shuffling symbols around, but it did not understand”.

Such people — let’s call them Searlites — have an intuition that “understanding” requires more than the “mere” mechanical processing of information, and thus they declare that a mere computer can’t actually “understand”.

The rest of us can’t see the problem. We — let’s call ourselves Dennettites — ask what is missing from the above robot such that it falls short of “understanding”. We point out that our own brains are doing the same sort of information processing in a material network, just to a vastly greater degree. We might suspect the Searlites of hankering after a “soul” or some other form of dualism.

The Searlites reject the charge, and maintain that they fully accept the principles of physical materialism, but then state that it is blatantly obvious that when the brain “understands” something it is doing more than “merely” shuffling symbols around in a computational device. Though they cannot say what. They thus regard the issue as a huge philosophical puzzle that needs to be resolved, and which may even point to the incompleteness of the materialist world-view. Continue reading

Basics of scientism: the web of knowledge

scientism A common criticism of science is that it must make foundational assumptions that have to be taken on faith. It is, the critic asserts, just one world view among other, equally “valid”, world views that are based on different starting assumptions. Thus, the critic declares, science adopts naturalism as an axiom of faith, whereas a religious view is more complete in that it also allows for supernaturalism.

This argument assumes a linear view of knowledge, in which one starts with basic assumptions and builds on them using reason and evidence. The fundamentals of logic, for example, are part of the basic assumptions, and these cannot be further justified, but are simply the starting points of the system.

Under scientism this view is wrong. Instead, all knowledge should be regarded as a web of inter-related ideas, that are adopted in order that the overall web best models the world that we experience through sense data.

Any part of this web of ideas can be examined and replaced, if replacing it improves the overall match to reality. Even basic axioms of maths and logic can be evaluated, and thus they are ultimately accepted for empirical reasons, namely that they model the real world.

This view of knowledge was promoted by the Vienna Circle philosophers such as Otto Neurath, who gave the metaphor of knowledge being a raft floating at sea, where any part of it may be replaced. As worded by Quine: Continue reading