Should You Judge What People Would Do, or What They Could Do?

Imagine you’re on a group project. Your friend Alex says they’ll handle the research. You know Alex has great intentions—they really mean it when they promise. But you also know, from past experience, that when Alex says they’ll do research, they almost always get distracted and end up doing nothing. You’d be better off assigning the research to someone else, even though Alex could do a fantastic job if they actually followed through.

Now here’s a strange philosophical question: Should Alex’s past pattern of failing matter when we decide what Alex ought to do?

One answer: Yes. What matters is what Alex would actually do if given the chance. If Alex would waste the opportunity, then Alex ought to step aside.

Another answer: No. What matters is what Alex could do. Alex could do great research, so Alex ought to do it—regardless of what would probably happen.

This disagreement is not just about group projects. It’s about a deep puzzle in ethics: When we figure out what someone morally ought to do, should we consider their actual weaknesses and habits, or should we consider only what’s possible for them?

Philosophers call this debate actualism vs. possibilism. And as you’ll see, it’s surprisingly tricky.

The Classic Case: Professor Procrastinate

The most famous example in this debate is called Professor Procrastinate. Here’s how it goes:

A graduate student asks Professor Procrastinate to review a paper that will be given as a job talk. The professor has three options:

Agree to review the paper AND actually review it. This would be best. The student gets a first-rate job offer.
Decline to review the paper. This is second-best. The student asks someone else, gets mediocre comments, and gets a second-rate job offer.
Agree to review the paper BUT NOT review it. This is worst. The student gets no job offer at all.

Here’s the catch: Professor Procrastinate has a terrible habit. If she agrees to review the paper, she will not actually write the review. She’ll get distracted, put it off, and never finish. This isn’t because she can’t write the review—she absolutely could. She just wouldn’t, as a matter of fact.

So the ranking looks like this:

Best: Agree AND review (but she wouldn’t do it)
Second-best: Decline (she would do this, and it’s not bad)
Worst: Agree AND not review (she would do this if she agreed)

Now: What ought Professor Procrastinate to do?

Possibilists say: She ought to agree to review. After all, agreeing to review is part of the best possible series of actions she could perform over her life. The fact that she wouldn’t follow through doesn’t change what she should do.

Actualists say: She ought to decline. What matters is what would actually happen. If she agrees, she’d bring about the worst outcome. So she should do the next best thing, which is decline.

Both answers seem pretty reasonable, right? That’s why this debate has been alive for decades.

The Core Disagreement

Let’s get more precise.

Possibilism: What you ought to do depends on what you could do, not what you would do. Your moral obligations are determined by the best series of actions that it’s possible for you to perform over your whole life. Your character flaws, bad habits, and predictable failures don’t get to change what you should do.

Actualism: What you ought to do depends partly on what you would do. If you know you’d mess up, that fact matters. Your actual behavior patterns help determine your obligations, because the goal is to bring about the best outcome given how you really are.

This is not a small disagreement. It leads each side to accuse the other of something pretty embarrassing.

The Problem with Possibilism

The main objection to possibilism is that it can tell you to do something that, if you actually did it, would lead to the worst possible outcome.

Remember Professor Procrastinate. Possibilism says she ought to agree to review. But if she follows that advice, she’ll end up not reviewing, and the student gets no job at all. That’s the worst outcome.

Now imagine a more extreme version: Suppose the student would be so devastated by getting no job offer that they would commit suicide. Possibilism still says Procrastinate ought to agree to review. The terrible consequence doesn’t change the obligation—because what matters is that she could have done the right thing, not that she would have failed.

This strikes many people as deeply wrong. If you know you’d mess up, shouldn’t you avoid the mess? Shouldn’t you do the next best thing rather than the best thing you won’t actually complete?

Possibilists have a response. They say we need to distinguish between two kinds of obligations:

Unconditional obligation: What you ultimately ought to do, full stop. That’s to agree AND review.
Conditional obligation: What you ought to do given that you won’t fulfill your unconditional obligation. That’s to decline, since you won’t actually follow through.

So the possibilist can say: Procrastinate’s unconditional obligation is to agree and review. But since she won’t, she acquires a conditional obligation to decline. It’s not that the possibilist can’t see the practical problem—they just think we need more than one kind of “ought” to describe it.

The Problem with Actualism

Actualism has its own embarrassing consequence: it lets people off the hook too easily.

Suppose you have a friend who always breaks promises. They say they’ll help you move, but they never show up. According to actualism, if you ask this friend to help, they should say no—because saying yes would lead to a broken promise, which is worse than just saying no from the start.

But here’s the weird implication: The friend’s bad habit protects them from having an obligation to help. Their own unreliability means they don’t need to try. They get a “free pass” on their bad character.

Possibilists find this infuriating. They say: Your being the kind of person who would fail doesn’t get you out of your obligation. You’re still obligated to do the right thing—you’re just also someone who will fail. Actualism seems to reward bad character by lowering what’s expected of you.

Actualists bite the bullet: “Yes, if you know you’ll fail, maybe you should step aside. That’s not rewarding bad character—it’s being realistic about what will actually produce good results.”

A Middle Ground: Securitism

Some philosophers have tried to find a middle path. Their view is called securitism.

The key insight is this: Sometimes you can change what you would do. If you only knew you’d procrastinate, maybe you could set up systems to stop yourself. Maybe you could tell a friend to check on you, or you could start the work immediately rather than promising to do it later.

Securitists say: An obligation applies only if you could, at the moment of deciding, actually secure the good outcome. If you’re currently able to form an intention that would lead you to follow through, then you ought to try. But if even your best present intention wouldn’t change what you’d later do—if you genuinely cannot control your future self—then you should consider that future self almost like a different person, and plan accordingly.

This puts securitism somewhere between actualism and possibilism. It cares about what you could do right now to shape your future behavior. It doesn’t let you off the hook just because you have bad habits you could overcome. But it also doesn’t pretend your future failures don’t exist if they’re genuinely outside your control.

Why This Matters Beyond Philosophy Class

You might think this is just academic navel-gazing. But these ideas show up everywhere:

In school: Should a teacher give a student a challenging assignment they could do brilliantly but might not finish, or an easier assignment they’ll definitely complete?

In friendships: If you know your friend tends to flake out, should you still invite them to big plans, or should you only make low-stakes plans?

In real ethics debates: When we think about what society owes to people who have made bad choices, should we consider what they could have done (and blame them for not doing it), or what they would have done given their circumstances?

In your own life: When you decide whether to take on a big goal, should you think about the best version of yourself that could succeed, or the actual you that might quit partway through?

There’s no settled answer to these questions. Philosophers still argue about them. But thinking about the puzzle forces you to decide what kind of “ought” really matters: the one based on your best possible self, or the one based on who you actually are.

One Last Twist

Here’s something strange: Both views seem to get things backwards in some cases.

Imagine a mass murderer who, right now, wants to kill someone. But if he kills one person now, he’ll feel satisfied and stop. If he kills no one now, he’ll later kill ten people.

Actualism says he should kill one person—because that prevents a worse outcome. But that seems awful: telling a murderer to kill someone?

Possibilism says he shouldn’t kill anyone—because killing is wrong. But that means ten people die instead of one.

Which is worse: telling someone to do something terrible to prevent something even more terrible, or refusing to compromise and letting the worse thing happen?

There’s no comfortable answer. And that’s exactly why philosophers keep arguing about this.

Appendix

Key Terms

Term	What it does in this debate
Actualism	The view that you should consider what you would actually do when deciding obligations
Possibilism	The view that you should consider only what you could possibly do when deciding obligations
Securitism	A middle view that asks whether, right now, you can secure the good outcome through your present intentions
Maximal act-set	The complete series of actions you could perform over your entire life
Counterfactual	A “what-if” statement about what would happen under different circumstances
Conditional obligation	What you ought to do given that you won’t fulfill your primary obligation

Key People

Holly M. Smith (née Goldman): The philosopher who first carefully defined and defended actualism, using cases like Professor Procrastinate. She later revised her own view to handle more complicated cases.
Michael Zimmerman: A leading defender of possibilism, who argues that your moral obligations depend on what you can do, not on your character flaws.
Douglas Portmore: A defender of securitism, who argues that the right view depends on what you can currently control about your future actions.

Things to Think About

Suppose you know you’ll procrastinate on a big assignment. Should you turn it in early even if it’s worse quality, or should you aim for the best version even though you’ll probably fail? Does your answer change if a friend’s grade depends on yours?
Is there a difference between “I couldn’t do the right thing” and “I wouldn’t do the right thing”? When should a person’s past failures count as evidence that they can’t succeed, not just evidence that they won’t?
If you could change your own personality (become more disciplined, less lazy, more courageous), do you have an obligation to do so? Or is who you are right now what matters for your current obligations?

Where This Shows Up

In video games: When you know you’ll get distracted and abandon a character build, should you choose a simpler build that you’ll actually finish?
In sports: If you know you’ll lose focus in the last quarter, should you pace yourself differently?
In climate debates: Should we aim for the best possible environmental policies (that we might not achieve), or settle for good-enough policies we can actually pass?
In mental health: Should we hold people responsible for what they could do if they weren’t struggling, or for what they can actually manage right now?