 The Treatise begins with setting up a “scheme of fundamental ‘elements’” for analyzing human phenomena in terms of ideas and impressions. Humean analysis begins with phenomena from the historical and everyday observation of human behavior, and the analysis proceeds by “experiments … judiciously collected and compar’d” (THN I.10), in order to arrive at analogies among various instances “from the observation of several parallel instances” (EHU 8.13). The products of comparative analysis so conducted are the principles of various faculties, like perception, imagination, reason, etc., whose interaction results in ideas and impressions causing behaviour, but their contribution can hardly be measured and the principles of their interaction can hardly be quantified—not even in principle, so they cannot be mathematized either (see also  section 4.6  above). Instead, they remain qualitatively different principles of human nature, and the explanation of human phenomena consists in a description of how these principles with their distinctive characteristics figure in producing them (Demeter 2016).