One of the most deceptively simple words in the legal vocabulary is “reasonable.” It’s everywhere — in contract law, torts, employment disputes, even criminal defences. We are constantly asking:
What would a reasonable person have done?
Was that response reasonable?
Did the employer act reasonably under the circumstances?

And yet, behind this one word lies an entire world of legal ambiguity, discretion, and evolution. Today, I want to explore what “reasonableness” really means in law, why it's not as neutral as it sounds, and what it tells us about how the law balances principle with real-world complexity.

A Principle Rooted in Context

Unlike statutory tests or formulaic procedures, “reasonableness” is an inherently contextual concept. It requires courts to step into the shoes of an imagined neutral observer — the “reasonable person” — and evaluate actions against a standard that’s deliberately flexible.

In negligence law, it’s the classic benchmark:

Did the defendant breach their duty of care by failing to act as a reasonable person would have?

In employment law, tribunals weigh whether a dismissal or a disciplinary procedure was carried out “reasonably” — not just legally.

In criminal law, “reasonable force” is central to self-defence arguments. And in public law, reasonableness determines the limits of discretion, especially when authorities make decisions that impact rights and livelihoods.

The Reasonable Person Is Not Always You

The tricky thing is, “reasonable” isn’t universal. The courts have long held that the standard is objective — but it adapts depending on the context.

For example:

  • In medical negligence, the “reasonable” doctor standard depends on accepted clinical practice.
  • In contractual interpretation, reasonableness factors in industry norms and bargaining positions.
  • In harassment claims, the test includes both subjective experience and objective impact.

So no — it’s not what you or I think is fair. It’s what the court thinks a hypothetical, informed, careful person (or body) would have done. It is, in every sense, a construct. And it’s this legal fiction that allows for some of the law’s most interesting — and contested — judgments.

Why It Matters More Than Ever

In a legal landscape increasingly shaped by discretion — from police powers to workplace disputes to AI-based decision-making — the idea of “reasonableness” is doing more and more work.

That’s not always a good thing.

Because reasonableness is elastic, it can:

  • Mask implicit bias in decision-making (“it seemed reasonable at the time”)
  • Justify flawed processes under the banner of discretion
  • Make outcomes harder to predict — especially for self-represented litigants or those outside traditional legal frameworks

And yet, its flexibility is also what makes it essential. The law isn’t rigid. It breathes. “Reasonableness” is how it breathes.

Final Thought

Studying or working in law means making peace with ambiguity. But we don’t have to be passive about it. Understanding how and why the courts deploy “reasonableness” empowers us to scrutinise, challenge, and frame better arguments.

Whether you're assessing employer conduct, reviewing public decisions, or defending actions in tort, remember: “reasonableness” is never just a word. It’s a judgment call. And that call deserves to be examined, every single time.