Mark Dsouza


One of the first things that every law student learns in their criminal law module is that, in general, the criminal law is interested in acts rather than omissions. Sure, in some cases, the criminal law will also punish omissions, but those are exceptional. Now, perhaps as an empirical claim, that is fair enough, but do we have good normative reason to systematically prefer criminalising acts rather than omissions? In my recent article in the Northern Ireland Legal Quarterly, I argue that we don’t.

To see that, we must be careful to exclude considerations that have hitherto tended to skew our analysis. For instance, we should only compare ‘true’ omissions (as opposed to mere non-doings) with acts. I don’t omit to see infra-red light, or to log into a WiFi network if I don’t realise it is available, or to do my morning meditation if I never start my day with meditation. So we can’t sensibly compare these non-doings with acts when we consider appropriate targets for criminalisation. I argue that only non-doings that

a are ‘performed’ by persons exercising their practical capacity for voluntary control, and
b belie a contextually salient (i.e. stemming from societal morality or routine), imperative, liberty-limiting expectation

are ‘true’ omissions.

We must remember also that for our purposes, the act/omission distinction is relevant only to the conduct element of the actus reus of a prima facie criminal offence. Plenty of factors apart from our selection of the qualifying conduct token affect criminal liability, including other parts of the actus reus, the mens rea and defences. Therefore, in comparing acts and omissions we must (1) be wary of drawing conclusions directly from criminal liability outcomes and (2) exclude or neutralise from test cases any matters relating to factors other than the offence’s conduct element.

The conduct element of an offence picks out deviations from our baseline expectations about how the world will be. An act can cause such a deviation, but we can now see that so can a ‘true’ omission. So, unless we are given reason to think otherwise, we should treat omissions as being as capable as acts of satisfying the conduct element of any offence we want to create.

Several theorists have tried to offer us reasons to think otherwise. Four such arguments still command some support. Consider these in turn.

1 Authorship/responsibility: Some argue that when we author the stories of our lives by interacting with our environment and other people, we do so primarily through our acts, and only secondarily through our omissions. This, for them, justifies the primacy of act-based criminalisation. But there isn’t much evidence for this claim. Sure, much of our vocabulary of causation is act-normative, but that isn’t a reliable indicator of how we are hardwired to make sense of our interactions with the world. Even (generously) assuming that this isn’t an English-specific phenomenon, language patters may reflect merely the relative frequency with which we interact with the world through acts and omissions. But frequency does not suggest primacy; if it did, we should be branding left-handed people as deviants or inferior. (Please don’t!) We actually author both, our chosen doings and our chosen non-doings. We can sensibly say ‘I wish I’d called tails’ or ‘I saw that lottery ticket, but didn’t buy it’. In this wide sense, authorship isn’t very instructive. It supplies no reason to distinguish between doings and non-doings, let alone acts and omissions, in criminalisation contexts.

2 Causation: Another claim is that we cause things by our acts, whereas our omissions merely let things happen. Perhaps that is true in physics. But in law (and ordinary speech) the attribution of causal responsibility is a normative as well as mechanical issue. So, we commonly use the language of causation to pick out the most salient ingredients in the occurrence of an event – even if they are omissive – as their causes. That’s why my omission to latch the window causes it to slam in a storm.

3 Wrongness/culpability: Still others suggest that harming by act is either more wrongful, or more culpable, than harming by omission. But these claims do not survive close examination. The wrongness argument rests on a failure to properly distinguish between non-doings and omissions, and the culpability argument conflates intuitions about an actor’s blame for a particular event (which are relevant), and her likelihood to pose a future threat, or how much regret she will feel (both of which are not).

4 Liberty: Even so, we might think that prohibiting an act leaves us more surviving options (‘You can do anything but X’) than prohibiting an omission (‘You can do nothing but X’). So, to better protect liberty, we should prefer to prohibit acts rather than omissions. But the liberty gap is smaller than one might initially think. If ‘X’ refers to a broad class of things, prohibiting it may destroy several options (‘You cannot leave the prison cell’), and prohibiting its omission may be less restrictive than previously thought (‘You must provide reasonable assistance to V’, where a plethora of measures are considered ‘reasonable assistance’). Besides, we can multitask – if we are prohibited from omitting X, we can do X, and anything that is compatible with doing X. Moreover, we typically prohibit acts in perpetuity (‘You should never kill a person’), but prohibit omissions ie, require acts, only fleetingly (‘Pull over, while this emergency vehicle crosses’). Finally, we can adjust variables other than the conduct element of an offence to achieve the desired balance between our interest in liberty and our interest in other values like security and solidarity. So, we can expect less of people (‘Call the fire brigade!’, rather than ‘Run into a burning building to rescue someone!’), or link our expectations to the actor’s role (laypersons need do less than firefighters), or adjust the threshold for a duty to act to arise (you must act if necessary to ‘avert imminent serious bodily harm’, not to ‘minimise eventual minor property damage’), and so on. Since well-drafted omissions-based criminal liability can adequately be liberty-respecting, this argument too cannot support systematically distinguishing between acts and omissions in our criminalisation decisions.

I therefore conclude that while the act/omission distinction is a fairly good rule of thumb, it does not deserve its foundational place in criminalisation theory.