The atomic theory of matter and the periodic table of elements allow us to understand the physical nature of material objects, including living beings. Quantum theory illuminates the physical basis of the periodic table and the nature of chemical bonding. Molecular biology shows how complex molecules underlie the development and functioning of living organisms. And neurophysics reveals the functioning of the brain.
In the hierarchy of complexity, each level links to the one above: chemistry links to biochemistry, to cell biology, physiology, psychology, to sociology, economics, and politics. Particle physics is the foundational subject underlying — and so in some sense explaining — all the others. In a reductionist world view, physics is all there is. The cartesian picture of man as a machine seems to be vindicated.