Is certainty confined to tautologies and introspection?

Is certainty confined to tautologies and introspection?

NB/ Although quite a specific topic, it is possible to get a b) question on this in the unit 1 examination for AQA philosophy. It's not as difficult as it sounds, but for both a) and b) questions which refer to this, candidates need to unpack the question carefully as follows.

• Tautologies are circular arguments which are known a priori through reason alone and are therefore immune to sceptical doubt. They are also known as analytical truths which are true by definition/in virtue of the meaning of the words involved. For example, "all bachelors are unmarried men" - this is certain.
• Introspection simply refers to the contents of our mind - the impressions, sense data and sensations that we have in our minds. This can be approached via either rationalist foundationalism, such as the cogito ('I think therefore I am') and the trademark argument for the existence of God which Descartes outlined. For empiricists such as Locke, this foundationalism and certainty applies only to the impressions themselves and not ideas or concepts we form from them as we may go wrong in inference. 
• This information is sufficient for an a) question but in b) questions candidates will have to evaluate the implications of this and whether it is the case.

Evaluation

• Empiricists such as Locke and Hume argue that although we…