Laws of form

also called the mark or cross, is the essential feature of the Laws of Form. In Spencer-Brown’s inimitable and enigmatic fashion, the Mark symbolizes the root of cognition, i.e., the dualistic Mark indicates the capability of differentiating a “this” from “everything else but this.”

In LoF, a Cross denotes the drawing of a “distinction”, and can be thought of as signifying the following, all at once:

• The act of drawing a boundary around something, thus separating it from everything else;
• That which becomes distinct from everything by drawing the boundary;
• Crossing from one side of the boundary to the other.

All three ways imply an action on the part of the cognitive entity (e.g., person) making the distinction. As LoF puts it:

“The first command:

• Draw a distinction

can well be expressed in such ways as:

• Let there be a distinction,
• Find a distinction,
• See a distinction,
• Describe a distinction,
• Define a distinction,

Or:

• Let a distinction be drawn.” (LoF, Notes to chapter 2)