A Critique of Postmodern Scepticism

In his 1996 essay Rethinking Democracy, neopragmatist philosopher Richard Rorty outlines four theses of postmodern scepticism [Rorty 2022:68].

Thesis 1 - There is no intrinsic character of reality, no one way the world is. No description of the world is closer to nature than any other.

Thesis 2 - There is no correspondence to reality to serve as the mark of truth. Rather, we call beliefs true when they seem better tools than any as-yet-imagined alternative beliefs.

Thesis 3 - Interpretation goes all the way down: there is no contrast between a fact and an interpretation except degrees of consensus: a "fact" is a widely accepted interpretation.

Thesis 4 - There is no objective fact about human beings which dictates our biological species should also be a moral community. The project of constructing such a community is one interpretation of the significance of the human existence among others.

What do these mean?

There are no facts in the traditional sense; everything is an interpretation. What we consider facts are merely interpretations that have gained a high degree of consensus. "Keir Starmer is the current Prime Minister of the UK" is an interpretation most people agree upon, thereby rendering it a "fact".

It follows from this that cosmopolitanism - the view that all of humanity constitutes a moral community - is an interpretation of the world, not a fact. Other interpretations, such as ultranationalism, which posits that one nationality is a superior distinct moral community to others, exist in conflict with it. Rorty argues that there are no moral facts, or objective universal truths, that dictate humanity is a moral community. He isn't necessarily arguing against the desirability of such a community, but rather against the notion of moral facts in the first place.

One of the challenges of moral realism - which asserts that there are objectively true moral facts - is that it doesn't explain how these moral facts correspond to reality. Where are they? What are they? How did they arise? Why are there moral facts? The answers to these questions are less than satisfactory. Simply saying "they just are" isn't much of an answer. Claiming that God made them so is problematic for atheists or agnostics, and it's unclear how the Big Bang relates to the creation of moral norms. Instead, Rorty suggests that morals are interpretations of the world, and what matters is their usefulness in improving our ethical behaviour.

Postmodern scepticism goes much further than denying "moral facts". It asserts that no facts correspond with the world. For example, if you see a red apple in front of you and state "there's a red apple in front of me", its truth is not determined by the red apple being in front of you. Instead, it's the usefulness of it being the best belief at our disposal which makes it true. Claiming "there's a red banana in front of me" would be far less useful and therefore false.

Thesis 1 is the most challenging to grasp. What does "intrinsic character of reality" mean? What does "no one way the world is" mean? The "intrinsic character of reality" is the essence of reality. For instance, if you are a pantheist, then you'll believe that God is the very essence of reality - "the intrinsic character of reality". God is reality and reality is God. This is what Baruch Spinoza argues in his famous treatise Ethics.

"No one way the world is" either means there are multiple ways that the world can manifest, or the interpreted. Rorty is asserting that our theories about reality are mere interpretations. We can refine these interpretations at will which entails there is no single description of the world that fully captures it.

Positivistic Pragmatic Epistemology Contra Postmodernist Scepticism

Newtonian Mechanics and Quantum Mechanics

Newtonian and quantum mechanics are excellent examples demonstrating the soundness of pragmatism. The usefulness of both theories in predicting reality which defines their worth, not their correspondence with reality. Neither describes the actual world for varying different reasons.

Newtonian mechanics treats space and time as absolute, with time passing uniformly regardless of what's happening in the universe. However, we know from general relativity that is not the case. As you approach the speed of light or move near very strong gravitational sources like neutron stars or black holes, time passes much slower. Physicists call this time dilation. Christopher Nolan's Interstellar illustrates this with the water planet orbiting the black hole Gargantua, where an hour on the planet is equivalent to decades on Earth.

Quantum mechanics, on the other hand, tells us nothing concrete about reality at the quantum scale. David Mermin famously summed this up by saying, "shut up and calculate!" Quantum mechanists use their equations predicting reality without delving into how these equations relate to reality.

The predictions of quantum mechanics enabled the engineering of semiconductors which would have been impossible otherwise. Furthermore, quantum mechanics is the most thoroughly and accurately tested scientific theory in history. All this despite the fact quantum physicists don't know what the equations mean as far as reality is concerned.

Does Newtonian and Quantum Mechanics give credence to postmodernist scepticism?

Prima facie, it might seem so. The wave function in quantum mechanics - which represents all the possible configurations of a quantum system - suggests there is "no one way the world is". The Heisenberg and Schrödinger equations are equivalent perspectives describing the same quantum reality, which aligns with thesis 3. Neither Newtonian nor quantum mechanics corresponds to reality, making both consistent with thesis 2.

Scientists establish confidence in their results through methods like the "five sigma" test. It's the burden of proof scientists must satisfy before announcing a result. Data contains random fluctuations which can give the impression that a phenomena exists which doesn't. Removing the impact of those fluctuations is key for scientists in reaching a firm conclusion about what the data tells them.

Let's consider the example of the discovery of gravitational waves. Scientists take the mean of the entire data set. This mean is essentially the typical background noise of the data. Physicists compare the data at the specific instance they believe a gravitational wave was detected with the whole sample. They calculate how far away the suspected gravitational wave data is from the mean. Statisticians call this the standard deviation, 𝝈. Physicists know that a low standard deviation means the suspected gravitational wave was likely just random fluctuations. In contrast, physicists know that a high standard deviation makes it improbable that random fluctuations caused the gravitational wave like phenomena in the data set. In fact, physicists have good grounds for believing they have detected something worthy of peer review.

A 5-𝝈 test ensures that the observed phenomena are almost certainly real, as used in confirming the existence of the Higgs boson. A 3-𝝈 test, in contrast, allows for some statistical interference, but provides a result supporting the hypothesis in question.

Statistical reasoning, not consensus, determines how effective a test was at uncovering the investigated phenomena. Consensus arises only after a hypothesis satisfies the "n-𝝈" test, where n denotes the number of standard deviations from the mean. The other consensus is within the methodology itself, based upon the mathematics of probability theory. This is a consensus of the validity of the scientific method, not a consensus of any result we arrive at from that method. Consequently, facts do exist.

Postmodern sceptics falsely conflate the sociology of knowledge - the social process by which we acquire knowledge - with epistemology - the study of how knowledge is acquired. By ignoring epistemology, the postmodern sceptic assumes that sociological descriptions of how we acquire knowledge is all that matters. Thomas S. Kuhn's The Structure of Scientific Revolutions is not an attack on the validity of the scientific method, but a description of the sociology of scientific knowledge and associated revolutions. Scientists are not adherents of the scientific methods. They have their own pet theories and biases rejecting theories like Quantum Mechanics. Albert Einstein himself was guilty of this.

"I, at any rate, am convinced that [God] does not throw dice" - Albert Einstein

Einstein refused the probabilistic interpretations of quantum mechanics because it didn't fit with his conception of physical reality - a stance some consider his greatest mistake. Einstein faced the same resistance with his theory of special and general relativity. The old guard refused accepting a relativistic space-time instead of an absolute space and time as described by Isaac Newton. As a community scientists are resistant to change. Quantum mechanics baffled physicists so much that sociological factors did not have any role in the creation of quantum mechanics. Quantum physicists successfully predicting phenomena like the double-slit experiment confirmed the theory. It was the epistemic veracity of the scientific method which gave the pioneers of quantum mechanics the social power for initiating another scientific revolution.

Postmodern scepticism is simply another form of philosophical scepticism, which serves no practical purpose. Philosophical scepticism, which denies that any knowledge is possible, is different from scientific scepticism, which rejects knowledge for specific claims. What practical contributions have philosophical or postmodern scepticism made? Scientific scepticism's utility is obvious. Richard Rorty's postmodern scepticism is inconsistent with his pragmatism; by embracing postmodern scepticism, he ceases to be a pragmatist.

Moral Philosophy and Postmodern Scepticism

The scientific method tells us nothing about what is right and wrong. How do we acquire moral knowledge? What is the epistemology of moral philosophy and ethical norms? While these are important questions, they're not directly relevant for our purpose here. So far, we have concluded that Theses 1-3 are not true.

For the sake of argument, let's suppose Thesis 4 is true. While moral philosophers speak of moral facts, no satisfactory explanation for what they are and how they arose exists. Perhaps we can take inspiration from Baruch Spinoza: if we identify the universe with God and God with the universe, then ethical norms would be a natural extension of both. However, most philosophers are atheists, who like the scientist Laplace, don't need that hypothesis.

Let's take the atheist position. Does this validate the postmodern sceptic? No! Moral philosopher J.L. Mackie famously argued for moral nihilism, claiming there are no moral facts. Either they're all false, or they're neither true nor false. Mackie did not use postmodern philosophy in arguing for what he called Error Theory in meta-ethics. However, utilising pragmatism we can still argue for progress in ethical behaviour. How does one's behaviour contribute to their mental health? How does the quality of their character meet the needs of the day? How does such behaviour enforce the health of the society and polity as a whole? Just because we cannot establish the existence of moral facts does not mean ethics is impossible.

Conclusion

In the spirit of epistemic pragmatism, when it comes to postmodern scepticism French physicist Pierre-Simon Laplace puts its best:

"Je n'avais pas besoin de cette hypothèse-là."

QED.

Bibliography

Rorty, R. Ed: Malecki, W.P. and Voparil, C. 2022 What can we hope for? - Essays on Politics. Oxford: Princeton University Press