The view that the mind is a tabula rasa (blank slate) at birth is held by empiricist philosophers such as Hume and Locke who deny the existence of non trivial, substantive a priori knowledge (apart from Mathematics although J.Mills also disputes this). They argue that all non trivial ideas and knowledge are derived from sense experience, a posteriori.
1. Locke's blind man can be used to argue that we need the corresponding sense organ in order to have an idea of something e.g. a blind man has no sense organ of sight and can therefore not have the experience of seeing red and thus can't have the idea/concept of red in his mind.
-But, it can be argued that we do have ideas of things that we've never experienced for example, ultraviolet light and the idea of a unicorn.
-Hume argues that the complex idea of a unicorn can be broken down into simple ideas which are derived from experience. For example, my experience of a horse and my experience of a rhino's horn put together. Concepts come from sense impressions which they copy. And abstract concepts such as justice, although not traceable to one specifiable sense experience they are formed by generalising experiences e.g. a just act that I've witnessed through induction.
-There are various problems with Hume's argument in that how do we know how far to break simple ideas down? The simple idea of a horse can be broken down into the smell of a horse and the sight of a horse or it's tail and torso for example.
-Also, there is a lack of certainty with knowledge/ideas formed on the basis of introspection in that they are not immune to sceptical doubt because we assume that the future will resemble the past i.e. just acts that I've witnessed in the past will be similar now. (c.f. russell's turkey)
2. Examples of innate knowledge/ideas can be used to show that knowledge can also come from before birth, i.e. not via sense experience - our minds are not a tabula rasa. Plato's theory of the form of beauty can be seen as innate because we can never experience true beauty in the world and so it must be innate in order to link beautiful things that have nothing else in common apart from this form e.g. we recognise that a painting and a face are both beautiful despite being very different.
-There are problems with Plato's form of beauty because beauty doesn't seem to be something universal e.g. in western cultures tanned skin is recognised as beautiful rather than pale skin in eastern cultures. If beauty is not universal, it can not be innate and must be derived through experience - through exposure to different cultures.
-Hume also argued that you cannot have an idea unless you have the corresponding experience, he gives the example of a laplander who has no idea of wine in their…