Augustine connects this with the problem of certainty. He says that we have immediate evidence of two things, namely, the logical form – because even the question of evidence presupposes the logical form – and secondly, the immediate sense experience, which should really be called sense impression because” experience'” is too ambiguous. What he means is this; I now say that I see blue. The piece of color may objectively be not blue but green – I sometimes confuse these two, especially in female dresses, (the horror of Mrs. Tillich!) – in any case, I now have blue, as sense impression. This is absolutely certain, even if the dress is not blue. Now this is what he means with immediacy. I see a man, but I come nearer and it is a tree, in reality; this often happens when you walk through a fog and cannot distinguish a man from a tree, if they are a little bit away from us. This means there is no certainty about the objective element in it, but there is absolute certainty about the impression I have as such. This means there is skepticism about everything real. Logical forms are not real; they are structures which make questions possible; therefore they are immediate and necessary.