 \((1')\), \((2')\) and \((3')\) do seem to give rise to sentences that intuitively must be true for all appropriate replacements of the letters “\(a\)”, “\(b\)”, “\(P\)”, “\(Q\)”, and “\(R\)”. And expressions such as “if”, “and”, “some”, “all”, etc., which are paradigmatic logical expressions, do seem to be widely applicable across different areas of discourse. But the idea that logical truths are or should be formal is certainly not universally accepted. And even among those who accept it, there is little if any agreement about what generic criteria determine the form of an arbitrary  sentence.[1]