How is Liberalism linked to Rationalism, and what are the implications of this link?

Liberalism, an ideology born out of the Enlightenment and the subsequent thirst for knowledge, seeks to base decision on empirical fact, or ‘a-posteriori’ knowledge. All liberals believe that humans are rational creatures, with a high capacity for learning and knowledge. Therefore, individuals are ‘ends in themselves’ (Kant), capable of discerning themselves what they need and desire, as well as being able to make decisions and think independently. Individual should always come first, and be ‘sovereign’ over his ‘own body and mind’. (Mill). This leads liberals to advocate for a Smithian free market economy, controlled by the ‘invisible hand’ of market forces, rather than the ‘dead hand’ of state intervention, where all rise and fall on the basis of their own merit, with ‘heaven’, helping those ‘who help themselves’ (Smiles), and ‘the drunk in the gutter’ being ‘just where he deserves to be’ (Sumner). Furthermore, it leads liberals to advocate in favour of a small, meritocratic ‘nightwatchman’ state (Locke) that only serves to defend the realm and guarantee freedom, (for ‘where there is no law, there is no freedom’ (Locke)), and is based around the Spenserian principle of ‘survival of the fittest’. Likewise, due to rational humans being able to discern which are best and which are failures, society will evolve into a ‘marketplace of ideas’, where the best rise and the worst fall (Mill).