The fact that everything that is not forbidden by laws of nature is achievable, given the right knowledge. ‘Problems are soluble.’ – The ‘perspiration’ phase can always be automated. – The knowledge-friendliness of the physical world. – People are universal constructors. – The beginning of the open-ended creation of explanations. – The environments that could create an open-ended stream of knowledge, if suitably primed – i.e. almost all environments. – The fact that new explanations create new problems.