In a world where "follow the science" has become a mantra for everything from public policy to personal beliefs, it's easy to slip into scientism, the idea that science isn't just a powerful tool for understanding the universe, but the criterion for truth. Scientism posits that if something can't be empirically tested, measured, or falsified through scientific methods, it's not really knowledge or truth at all. Philosophy? Art? Ethics? Spirituality? Dismissed as mere opinion or superstition unless they pass the lab test.

But hold up, is this rock-solid? Or is it built on shaky ground? Today, I'm dipping into a classic philosophical takedown: the problem of the criterion, courtesy of the ancient sceptic Sextus Empiricus (c. 200 AD). This isn't just dusty old Greek wisdom; it's a timeless challenge that exposes scientism as either circular, infinitely regressive, or dogmatically asserted. Buckle up your lab coat for a refutation that might make you question your faith in the white coat!

What Is Scientism, Anyway?

Let's clarify terms. Scientism isn't science itself, science has given ussmartphones, and a glimpse into the cosmos. Scientism is the overreach: the belief that scientific methods are the only reliable way to determine what's true. Proponents like Richard Dawkins or Sam Harris argue that questions about morality, meaning, or even consciousness, should be handed over to science, or they're not worth asking. Worse, if phenomenon like consciousness are not reducible to physics, then they don't exist (so called eliminative materialism)! Yes, philosophers drawing taxpayers' money spend their time on such stuff!

The core claim? Science is the criterion of truth. A criterion is like a yardstick for judging claims, does it measure up? For scientism, if it's not observable, repeatable, and data-driven, it's out. But here's where the cracks appear: How do we know this criterion is the right one?

Enter Sextus Empiricus, a second-century AD philosopher from the Pyrrhonian sceptic school. He wasn't anti-knowledge; he was anti-dogma. In his Outlines of Pyrrhonism, he poses the "problem of the criterion," a trilemma that traps any attempt to establish an ultimate standard for truth. Applied to scientism, it shows the whole edifice crumbling under its own weight.

The Problem of the Criterion: A Sceptical Trilemma

Sextus's argument boils down to this: To decide what's true, we need a criterion. But to justify that criterion, we face three bad options:

1.Circular Reasoning (or Question-Begging): We use the criterion to prove itself.

2.Infinite Regress: We need another criterion to justify the first, then another for that one, and so on forever.

3.Dogmatic Assertion: We just declare it true without proof, like a fiat from on high.

No escape hatch. It's like trying to pull yourself up by your own bootstraps — impossible. Now, let's see how this skewers scientism.

Option 1: The Circular Trap

Suppose a scientism advocate says, "Science is the criterion of truth because scientific evidence shows it's reliable." Sounds plausible at first, right? We've got centuries of successes: Newton's laws, Darwin's evolution, quantum mechanics. But wait, this is using science to validate science. It's like saying, "My ruler is accurate because it measures itself as one metre long."

The justification begs the question. To appeal to scientific evidence (experiments, data, peer review), you're already assuming science is the gold standard. Why not use philosophical reasoning or intuitive insight instead? Scientism can't answer without looping back: "Because science says so!" It's a cosy circle, but it doesn't prove anything to outsiders. Sextus would belly laugh — this is exactly the vicious cycle he warned about.

Option 2: The Infinite Regress Abyss

Okay, maybe we need something outside science to justify it. "Science works because it's based on reason and logic," the defender might say. Fair enough, but now we've introduced a new criterion: reason. How do we know reason is reliable? Do we test it scientifically? That brings us back to circle town.

If not, we need yet another criterion to validate reason, say, empirical observation. But how do we justify empirical observation? Another layer: perhaps consistency with reality. And on and on. This regress never bottoms out; it's turtles all the way down. Scientism promises certainty, but chasing justifications leads to an endless chain, leaving us with no solid foundation. As Sextus points out, without a stopping point, we can't even start judging truth.

Option 3: The Dogmatic Dodge

Faced with the above, some scientism fans might shrug: "Science just is the criterion — end of story. Look at its track record!" This is raw assertion, no different from a religious cultist declaring, "My cult is true because it's the word of our leader, who knows all." It's dogmatic, assuming what needs proving.

Why privilege science over, say, revelation or aesthetic experience? Without argument, it's arbitrary. Sextus calls this "bare assertion," a cop-out that sidesteps the hard work of justification. In a diverse world, this smells like intellectual imperialism … science rules because... we say so! Not convincing.

Beyond the Trilemma: Why This Matters

Sextus's problem isn't just a gotcha; it highlights scientism's limits. Science excels at "how" questions (How does gravity work? How do cells divide?), but flounders on "why" or "ought" (Why are we here? What should we value?). Claiming science as the sole truth-criterion dismisses vast swaths of human experience, love, justice, beauty, as illusory. Yet these aren't scientifically verifiable, but they're real to us.

Moreover, science itself relies on non-scientific assumptions: the uniformity of nature, the reliability of induction, even mathematics axioms, and these can be shown not to be capable of proof of consistency, if consistent at all. These are philosophical priors, not lab results. Scientism saws off the branch it's sitting on.

Don't get me wrong — I'm not anti-science: after all, I am Professor X! I'm pro-humility, and pro-Christian. Science is a fantastic method, but not the only one. Philosophy, history, art, religion, and yes, even scepticism, enrich our understanding.

Wrapping It Up: Embrace the Uncertainty

In the end, Sextus Empiricus reminds us that chasing an ultimate rational criterion is futile. Scientism's claim that science is the yardstick of truth falls into the trilemma: circular, regressive, or dogmatic. It's a seductive illusion in our data-driven age, but it doesn't hold up.

So, next time someone shouts "Scientism forever!", channel your inner sceptic. Ask: By what criterion? And watch the house of cards tumble. Truth might be messier than a controlled experiment, but that's what makes the quest worthwhile.