What is Biological Naturalism?

Biological Naturalism is a theory developed by John Searle who sought to end the relentless debate between materialists and dualists. As the name of the theory suggests, Biological Naturalism (BN) is created from theories within biology and most specifically evolution. BN argues that every aspect of human beings have a purely physical origin, consciousness is an aspect of human beings and therefore consciousness has a purely physical origin. Searle argues that consciousness is an emergent property of our brain i.e. it is causally reducible to our physical brain. When biological processes reach a certain point of organisational complexity, new phenomena such as consciousness emerge. Consciousness is a higher-level state of the brain. Although consciousness emerges from lower level states of the brain it is not reducible to these lower level states, therefore we can say consciousness is causally reducible but not ontologically reducible. Mental states are caused by non-mental states however they cannot be reduced to these physical states. Furthermore consciousness supervenes brain processes; any changes in consciousness requires in brain processes. Consciousness and physical brain processes are inextricably linked. Searle uses the analogy of the wetness of water to help illustrate his theory. We experience water to be wet, however the macro property of wetness is caused by the micro level of water: millions of individual and invisible molecules each made up of two hydrogen atoms and one oxygen atom. Similarly, conscious states are caused by non-conscious micro- neurological states. Although Searle acknowledges that no analogy is perfect he believes this best helps understand the theory.