That Big Science culture in the USA, and similar groups elswhere, tended to have separate, direct access to government and hence to funding sources. … - Philip W. Anderson

I learned, practically in my cradle (actually from Bill McMillan's thesis), that the ground state wave function of a system of bosons should necessarily be real and positive, a fact which made his early Monte Carlo simulations infinitely easier.

The behavior of large and complex aggregates of elementary particles, it turns out, is not to be understood in terms of a simple extrapolation of a few particles. Instead, at each level of complexity entirely new properties appear, and the understanding of the new behaviors requires research which I think is as fundamental in its nature as any other.

Surely there are more levels of organization between human ethology and DNA than there are between DNA and quantum electrodynamics, and each level can require a whole new conceptual structure.