« A map is not the territory it represents. »AK
The non-identity principle is of a misleading simplicity: it establishes that two unspecified things cannot be identical under all the aspects. There are inevitable differences which can be more or less difficult to detect.
A corollary of this principle is that the words we use to speak about a thing are not this thing: a map is not the territory it represents.
When we say «This is a pencil», we blur the differences between 'pencil1', that we can touch, feel, use, etc., and an unspecified pencil. Thus, the aristotelian structure of our language encourages us to neglect differences. On the faith of the labels that we ascribe to objects, it is then easy for us to generalize, forgetting that this generalization concerns only labels, which are not the thing spoken about. We will call this semantic reaction 'identification'.
If we say, for example, «Man is an animal», the behaviour of animals can be considered as natural for man, implying the application of the so-called 'law of the jungle', 'law of the strongest' and individualism in human affairs.
How about the term 'dog'? The number of individuals with which any one is directly acquainted is, by necessity, limited, and usually is small. Let us imagine that someone had dealt only with good-natured 'dogs', and had never been bitten by any of them. Next he sees some animal; he says, 'This is a dog'; his associations (relations) do not suggest a bite; he approaches the animal and begins to play with him, and is bitten. Was the statement 'this is a dog' a safe statement? Obviously not. He approached the animal with semantic expectations and evaluation of his verbal definition, but was bitten by the non-verbal, un-speakable objective level, which has different characteristics.Alfred Korzybski, Science and Sanity, p. 373
To fight back this orientation and restore the natural order of evaluation, general semantics proposes the Structural Differential, visualizing the distinction between orders of abstractions, and extensional devices: