What counts as good evidence for a claim?

What this prompt is really asking

Each of the twelve TOK concepts gives you a different way into a prompt. These are the ones that do the most work here.

• Evidence

  Grounds of Knowledge · primary lens

  The prompt asks directly for the criteria that separate evidence with force from evidence that merely looks supportive.

  What is offered in support of a claim. Evidence is not the same as proof: it raises or lowers how likely a claim is, and its force depends on how it was gathered, what it was gathered for, and what else it is consistent with. Asking what would count as evidence against a claim is usually more revealing than listing evidence for it.

• Justification

  Grounds of Knowledge

  Evidence is only good relative to what it is being used to support, so the standard of justification sets the bar.

  The reasoning that connects evidence to a conclusion. Two knowers can hold the same evidence and be justified in different beliefs if their inferential standards differ. Justification is what separates knowing something from happening to be right about it.

Where the knowledge framework bites

Reached through this prompt’s concepts, in the framework’s canonical order.

Scope

Evidence: What a field can find evidence for marks the outer edge of what it can be about. Questions whose evidence is unobtainable in principle do not become open questions within a discipline; they fall outside its scope, and often get reassigned to another area of knowledge or to no one.

Justification: The strength of justification a field demands is calibrated to what it is for. A discipline whose errors are expensive sets a higher bar than one where a provisional answer is useful, so justification standards are partly a statement about a field's purpose.

Methods and tools

Evidence: Every discipline's methods are, in effect, a definition of what it will accept as evidence. A controlled trial, a dated document and a proof step are all evidence, but the practices that produce them are not interchangeable, and a method that cannot generate a certain kind of evidence will systematically miss the claims that would have needed it.

Justification: A discipline's methods encode its standard of justification: peer review, replication, source criticism and proof are all answers to the question of when an inference has earned its conclusion. Comparing those standards across areas of knowledge is more revealing than asking which is strictest.