 How (L1) and (L2) relate to each other is subject of controversy. One straightforward, though controversial view, is the following. For any given system of representations, like sentences in a natural language, there is one and only one set of logical constants. Thus there will be one formal language that best models what logically valid inferences there are among these natural representations. This formal language will have a logical vocabulary that captures the inferential properties of the logical constants, and that models all other relevant features of the natural system of representation with non-logical vocabulary. One especially important system of representations is our natural language. Thus (L1) is the study of formal languages of which one is distinguished, and this one distinguished language nicely represents the fixed and non-fixed features of our natural language, through its logical and non-logical vocabulary. And validity in that formal language, a technical notion defined in the appropriate way for that formal language, nicely models logical validity or logical consequence in our natural language system of representations. Or so this view of the relationship between (L1) and (L2) holds.