And whether pure concepts can be unearthed at all is doubtful, and with this we can ask whether they can as such exist (in the mind). I think they can, but only with qualification : Concepts are formed by, and on the basis of, sensory cognition of features. In each such a sensory cognition a relation of formal identity is established, that is, some part in the knowing power becomes, qua formal content, identical to a formal content in the extramental thing. In this way objective knowledge is guaranteed, and every sensory observation is ultimately infallible. A concept consists of many such formal contents amalgamated together. But this amalgamation is not infallible. Often, a concept is developing slowly and is consciously being amended many times (See the example of the true concept of a crystal, below). Nevertheless the concept remains a true natural and formal sign of its object, because it consists of formal contents of which at least some are identical to such contents in the extramental thing (while other formal contents of the alleged concept can later turn out to actually represent other things [i.e. the wrong things] ). In later documents of this Part of Website we will elaborate on this issue still further.