The physical origin of behaviour in biological organisms is distinct from those of non-living systems in one significant way: organisms exhibit intentionality or goal-directed behaviour. How may we understand and explain this important aspect in physical terms, grounded in laws of physics and chemistry? In this article, we discuss recent experimental and theoretical progress in this area and future prospects of this line of thought. The physical basis for our investigation is thermodynamics, though other branches of physics and chemistry have an important role. This article is part of the theme issue 'Thermodynamics 2.0: Bridging the natural and social sciences (Part 1)'.
Keywords: dissipative structures; end-directed evolution; machine conception of living organisms; machine paradigm of organism; self-healing; self-organization.