I wrote this post a while ago:
From the post:
Scientific work is not exclusively done at universities. Science is also practised by independent scholars all around the world, with or without a formal doctorate degree. Some are affiliated with independent research institutes such as Ronin Institute for Independent Scholars, Institute for Globally Distributed Open Research and Education (IGDORE) and CORES Science & Engineering. Others collaborate with friends and colleagues to start their own independent laboratories (e.g. Walden III), networks (e.g. SENS) or small research companies (e.g. Amber Biology). Yet others pursue science without being affiliated to any institute, network or company, which typically also mean that they conduct science without any funding or employment.