particle, modeled as a condensation within the Higgs field, corroborates aether, although physics need not state or even include aether. Organizing regularities of observations—as in the covering law model—physicists find superfluous the quest to discover aether. In 1905, from special relativity, Einstein deduced mass–energy equivalence, particles being variant forms of distributed energy, how particles colliding at vast speed experience that energy's transformation into mass, producing heavier particles, although physicists' talk promotes confusion. As "the contemporary locus of metaphysical research", QFTs pose particles not as existing individually, yet as excitation modes of fields, the particles and their masses being states of aether, apparently unifying all physical phenomena as the more fundamental causal reality, as long ago foreseen. Yet a quantum field is an intricate abstraction—a mathematical field—virtually inconceivable as a classical field's physical properties. Nature's deeper aspects, still unknown, might elude any possible field theory. Though discovery of causality is popularly thought science's aim, search for it was shunned by the Newtonian research program, even more Newtonian than was Isaac Newton. By now, most theoretical physicists infer that the four, known fundamental interactions would reduce to superstring theory, whereby atoms and molecules, after all, are energy vibrations holding mathematical, geometric forms. Given uncertainties of scientific realism, some conclude that the concept causality raises comprehensibility of scientific explanation and thus is key folk science, but compromises precision of scientific explanation and is dropped as a science matures. Even epidemiology is maturing to heed the severe difficulties with presumptions about causality. Covering law model is among Carl G Hempel's admired contributions to philosophy of science. See also Types of inference Deductive reasoning Inductive reasoning Abductive reasoning Related subjects Explanandum and explanans Hypothetico-deductive model Models of scientific inquiry Philosophy of science Scientific method Notes Sources Avent, Ryan, "The Q&A: Brian Greene—life after the Higgs", The Economist blog: Babbage, 19 Jul 2012. Ayala, Francisco J & Theodosius G Dobzhansky, eds, Studies in the Philosophy of Biology: Reduction and Related Problems (Berkeley & Los Angeles: University of California Press, 1974). Bechtel, William, Discovering Cell Mechanisms: The Creation of Modern Cell Biology (New York: Cambridge University Press, 2006). Bechtel, William, Philosophy of Science: An Overview for Cognitive Science (Hillsdale, NJ: Lawrence Erlbaum Associates, 1988). Bem, Sacha & Huib L de Jong, Theoretical Issues in Psychology: An Introduction, 2nd edn (London: Sage Publications, 2006). Ben-Menahem, Yemima, Conventionalism: From Poincaré to Quine (Cambridge: Cambridge University Press, 2006). Blackmore, J