``` Illocutionary force and semantic content are often taken to be distinct from one another, not just in the way that your left and right hand are distinct, but rather by virtue of falling into different categories. Stenius 1967 elucidates this distinction, noting that in chemical parlance a radical is a group of atoms normally incapable of independent existence, whereas a functional group is the grouping of those atoms in a compound that is responsible for certain of that compound's properties. Analogously, it is often remarked that a Proposition is itself communicatively inert. For instance, merely expressing the Proposition that it is snowing is not to make a move in a “language game”. Rather, such a move is only made by putting forth a Proposition with an illocutionary force such as assertion, conjecture, command, etc. The chemical analogy gains further support from the fact that just as a chemist might isolate radicals held in common among various compounds, the student of language may isolate a common element held among ‘Is the door shut?’, ‘Shut the door!’, and ‘The door is shut’. This common element is the Proposition that the door is shut, queried in the first sentence, commanded to be made true in the second, and asserted in the third. According to the chemical analogy, then:
Illocutionary force : Propositional content :: functional group : radical ```
