"According to act-utilitarianism, it is the value of the consequences of the particular act that counts when determining whether the act is right. Bentham's theory is act-utilitarian, and so is that of J.J.C. Smart.
One objection to act-utilitarianism is that it seems to be too permissive, capable of justifying any crime, and even making it morally obligatory, if only the value of the particular consequences of the particular act is great enough. Another objection is that act-utilitarianism seems better in theory than in practice, since we hardly ever have the time and the knowledge to predict the consequences of an act, assess their value, and make comparisons with possible alternative acts.
Modern act-utilitarians think that these objections can be met. Others have developed alternatives to act-utilitarianism, e.g. rule-utilitarianism, and other forms of indirect utilitarianism."
The Penguin Dictionary of Philosophy
ed. Thomas Mautner
Critique of Brave New World