Practical work (craftsmanship) usually profits by science and vice versa, but conflicts may appear. Knowledge in empirical science is declarative and general. Practical knowledge is »silent« and reflects the cumulated individual experiences within a profession. In a mature discipline like medicine, recognition of the unique value of the two kinds of knowledge protects against conflict. The police have only recently added science to govern practice. In addition, much of the police work is rule-governed and politically controlled – it does not reflect empirical knowledge. Explanations in natural science refer to Causes in the objective world. Meaning is the corresponding humanities key concept which is also highly relevant for police work. When conflicts arise – a dominant discourse may warp discussions. Examples of a set of such relevant conflicts are provided and discussed. Awareness and acknowledgement of the virtues and limitations of various knowledge forms are often lacking and leads to mutual disrespect. Such conflicts are currently difficult to resolve because the police leadership usually lacks practical police experience as well as training in empirical science. The presently weak voice of science should be strengthened by a full academization of the police in all Nordic countries.