 Still, by including commanding knowledge, the Visitor has left a middle ground between the purely theoretical and the practical. Certainly architecture is not practical since it does not directly produce anything, in the way carpentry does. However, it does give commands, whose effects are practical; thus, it is not for knowledge only, in the way in which calculation is for knowledge only. Insofar as architecture is an analogue for the political craft, the Visitor seems to be exploiting this middle ground (259e). It is as though the Visitor is trying to associate the political craft with the most abstract disciplines, like geometry, even though it has to have practical impact. In fact, including commanding knowledge under theoretical knowledge reflects again the tension between the knowledge needed to rule and the elaboration of that knowledge. The ruler needs to be able to engage in purely theoretical investigation; he also needs to bring order into the city. The Visitor turns to the latter activity when he compares the kingly or political knowledge to weaving. Finally, he arrives at the conclusion that the kingly knowledge weaves together all the other epistêmai — like generalship and judging — as well as the laws and those things having to do with the city (305e). While no resolution is offered to this tension, two features of this long discussion are suggestive. If the kingly or political epistêmê is like weaving, it depends on the ability first of all to distinguish what it will weave together. Insofar as dialectic is the skill of distinguishing the things known, it can serve as preliminary to weaving because it is preliminary to showing how the kinds harmonize. Further, if political knowledge is like architecture, it is a commanding knowledge (epitaktikê epistêmê); it gives commands. If we search for the source of these commands, a likely source is the relations and distinctions to be found among forms. If so, the abstract structures discovered by gnôstikê are normative for the city, the way the forms are in the Republic.