This paper examines, in the context of complicity as an example, how and why scholars theorise about the basis of the rules governing criminal responsibility and about the practice of the courts in imposing such responsibility and asks what sort of ‘impact’ of legal scholarship should be regarded as desirable or achievable or successful or should or can be sought. The methods and reasons of such scholars may include the habit and desire of providing explanations of the outcomes reached by the courts in particular difficult situations and may also involve developing justifications or critiques of them based on, or influenced by, theories of moral philosophy. This may also include a desire to influence future outcomes ‘in practice’ in related factual scenarios in a predictable and ‘just’ fashion consistently with the preferred theory. The paper examines whether the language in which (a contender for) a satisfactory explanation of a theory of derivative responsibility, expressed in terms inspired by George Fletcher, of complicity in wrongful even if excused conduct, can be (or has been) satisfactorily transposed into one expressed in language thought to be more amenable to the courts (such as ‘procuring an actus reus’). Case-law in this area is examined to see whether this sort of transposition does more harm than good and to what extent compromising or adapting an expression of principle in this manner may lead to unintended consequences. An alternative conclusion is also examined, which is that however carefully one formulates rules or statements of principle, unintended consequences will always or often follow and that this may not necessarily be a bad thing. Indeed, the ultimate conclusion may be that whilst having a beneficial influence on the substantive law may be a desirable impact which legal scholarship should aspire to or may be justified by, to adapt the words of John Gardner in a somewhat different context, having that impact should not be confused with trying to have that impact, since often it is the trying which is the problem (Offences and Defences (Oxford University Press, 2007) p 279).