[16] The self-contained nature of what can be experienced through ideas is not regarded by the naïve mind as being real in the same way that sense experience is. An object grasped in "mere idea" is regarded as a chimera until conviction of its reality can be given through sense perception. In short, the naïve man demands the real evidence of his senses in addition to the ideal evidence of his thinking. In this need of the naïve man lies the original ground for primitive forms of the belief in revelation. The God who is given through thinking remains to the naïve mind always a merely "notional" God. The naïve mind demands a manifestation that is accessible to sense perception. God must appear in the flesh, and little value is attached to the testimony of thinking, but only to proof of divinity such as changing water into wine in a way that can be testified by the senses.

[17] Even cognition itself is pictured by the naïve man as a process analogous to sense perception. Things, it is thought, make an impression on the soul, or send out images which enter through our senses, and so on.

[18] What the naïve man can perceive with his senses he regards as real, and what he cannot thus perceive (God, soul, cognition, etc.) he regards as analogous to what he does perceive.

[19] A science based on naïve realism would have to be nothing but an exact description of the content of perception. For naïve realism, concepts are only the means to an end. They exist to provide ideal counterparts of percepts, and have no significance for the things themselves. For the naïve realist, only the individual tulips which he sees (or could see) are real; the single idea of the tulip is to him an abstraction, the unreal thought-picture which the soul has put together out of the characteristics common to all tulips.