Many contemporary philosophers think that foundational beliefs still have to be based on evidence. But what evidence justifies foundational beliefs?
One option is to say that the evidence to which we must ultimately appeal consists in how things appear to be from our subjective perspective. For example, what justifies you in believing that there is a computer screen in front of you is the visual appearance that there is a computer screen in front of you.
Such liberal foundationalists claim that as long as you have no evidence to the contrary, you can be justified in believing that there is a computer screen in front of you on the basis of this appearance.
A different option is to hold that facts about the external world itself, not just appearances, can give foundational justification. On this view, sometimes called naïve realism, there is no ‘veil of appearances’ standing between ourselves and the world: when you open your eyes you can simply see that there is a computer screen in front of you, and you are thereby justified in believing this.