What is a tabula rasa?The empiricists held that humans are born as blank slates. This means that there are no 'innate ideas' -- ideas possessed at birth, prior to any experience. Locke used the analogy that the mind is a blank piece of paper, and that experience is what writes symbols on it.HUME'S ARGUMENTS:1. A blind man can never grasp the idea of the colour red. This shows that ideas are derived from experience. It follows that at birth, prior to experience, we would have no ideas -- we would be 'blank slates'.This observation is plausible. It provides an example of the view that ideas have their "origins in the senses", and that without those senses we would not have any ideas.However, Hume needs to establish that this holds for all of our ideas. Someone could consistently accept that the idea of red must be derived from sensation (and hence would not be present at birth), but deny that this held for all sensations. For example, it is not obvious that the ideas of God, the soul or power are derived from the senses, so generalising from one example is unconvincing.2. Hume issues the challenge to produce an idea that is not derived from experience. He argues that no such examples are to be found, and hence there are no counter-examples to the claim that all ideas are derived from sensation. This would have the consequence that we possess no ideas at birth, prior to having experience, and would hence be blank slates.If Hume is right to hold that there are no counter-examples to be found, then this would indeed vindicate the view that the mind is a 'tabula rasa' at birth. However, there are some weaknesses in the way he argues: he relies on empiricist accounts of e.g. the idea of God; he accepts the possibility of having an idea of a "missing shade of blue", which would be a counter-example; and he appeals to his doctrine that all ideas are derived from experience to deny that we have any idea of "occult qualities" -- this seems circular.