When I see a tomato there is much that I can doubt. I can doubt whether it is a tomato I am seeing or a cleverly painted piece of wax. I can doubt whether there is any material thing there at all. Perhaps what I took for a tomato was really a reflection; perhaps I am even the victim of a hallucination. One thing however I cannot doubt: that there exists a red patch of a round and somewhat bulgy shape, standing out from a background of other color patches, and having a certain visual depth, and that this whole field of color is directly present to my consciousness.