Distinguish between scientific and pseudoscientific claims, identifying characteristics of each

What this dot point is asking

NESA wants you to apply the criteria of science to evaluate whether a given claim is scientific or pseudoscientific, with named examples of each. This is the central topic of Module 7 and underpins everything else in Modules 7 and 8.

The answer

Science is a process of producing knowledge through evidence and self-correction. Pseudoscience uses the language and trappings of science but lacks its essential characteristics.

Characteristics of scientific claims

A scientific claim has these characteristics:

1. Falsifiability (Popper)

It can in principle be proven wrong by some observation or experiment.

2. Empirical basis

Supported by evidence collected through observation or experiment.

3. Peer review

Subjected to expert scrutiny before publication in reputable journals.

4. Replicability

Independent researchers can repeat the methods and obtain similar results.

5. Provisional and self-correcting

Updated when new evidence emerges; willing to revise core claims.

6. Mechanistic explanation

Provides a plausible cause linked to broader scientific knowledge.

7. Quantitative

Makes specific, measurable predictions where possible.

8. Open methodology

Methods are described so others can evaluate and reproduce them.

Characteristics of pseudoscientific claims

Pseudoscience presents the appearance but not the substance of science.

1. Unfalsifiable

No conceivable observation could disprove the claim. Defenders explain away contrary evidence.

2. Anecdotal evidence

Personal testimonials rather than controlled studies.

3. No peer review

Self-published, marketed directly to consumers.

4. Not replicable

Methods vague, proprietary or impossible to follow.

5. Resistant to revision

Defended even when overwhelming evidence accumulates against the claim.

6. No plausible mechanism

Either no proposed mechanism, or one inconsistent with established science.

7. Vague claims

Qualitative ("balances energy", "boosts immunity") rather than measurable.

8. Appeals to authority or ancient wisdom

Justified by celebrity endorsement or tradition rather than evidence.

The demarcation problem

The boundary between science and pseudoscience is debated by philosophers of science.

• Karl Popper (1934) proposed falsifiability as the criterion.
• Thomas Kuhn (1962) emphasised paradigms and normal-science problem-solving.
• Imre Lakatos (1970s) distinguished progressive from degenerating research programmes.

For HSC purposes, the Popperian framework plus the characteristics listed above is sufficient. NESA mark schemes reward students who apply criteria to specific examples rather than rote-listing definitions.

Worked comparison

Vaccination (scientific).

• Falsifiable: outbreak in vaccinated populations would disprove efficacy.
• Peer reviewed: tens of thousands of papers.
• Replicable: clinical trials independently confirm efficacy.
• Quantitative: 95 per cent efficacy with confidence intervals.
• Mechanistic: triggers adaptive immunity producing memory cells.
• Updated: vaccine schedules change as variants emerge.

Homeopathy (pseudoscientific).

• Practically unfalsifiable: defenders attribute failures to non-individualised remedies.
• Mechanism not plausible: dilutions of 10^60 leave no molecules of the original substance.
• Meta-analyses show no effect beyond placebo (NHMRC 2015).
• No coherent updating of theory in response to evidence.
• Marketed as alternative; peer review rare.

Science can be wrong

A common confusion: scientific claims can be incorrect, but science as a process self-corrects through peer review and replication. Pseudoscience can occasionally produce correct claims (a stopped clock is right twice a day) but lacks the systematic process that makes its successes reliable. The distinction is methodological, not about who happens to be right today.

Boundary cases

Some claims sit at the boundary.

• Acupuncture. Some controlled trials show modest pain relief; mechanisms remain debated. NHMRC reviews note moderate evidence for some pain conditions, weak or absent for many other claimed indications. Partially scientific, partially marketed pseudoscientifically.
• Nutritional supplements. Some claims (vitamin D deficiency correction) are evidence-based; others (anti-ageing claims) are not.
• Psychology and economics. Sometimes criticised as "softer" sciences. Reproducibility crisis has spurred reforms.

These boundary cases show that the distinction is not always binary, but the criteria above let students reason about specific claims.