Tunable matter as a unifying paradigm for biological function

I suggest that it is useful to think of living systems as composed of tunable matter, i.e., as collectives of heterogeneous physical components whose effective interactions (characterized by degrees of freedom) can be individually tuned to satisfy design and physical constraints required for collective function. We are all familiar with the genome, whose sequence is adjusted via mutation, recombination, and selection to increase organismal fitness. We also understand the brain as having synaptic connections tuned on far faster time scales than evolution. Statistical physics has made dramatic progress in understanding neural systems, beginning with the celebrated Hopfield model in which synaptic DOFs are tuned via the process of Hebbian learning to acquire the function called associative memory. The tunable matter paradigm generalizes this logic beyond the genome and brain, extending it to new classes of degrees of freedom, tuning processes, and biological functions. I will discuss a few examples to demonstrate how to use this conceptual approach to gain useful insight into the emergence of collective biological function.