Alternative Categories​

• Symbolic: propositional (Camp 2018), discursive (Fodor 2007)
• Iconic: analog (Beck 2018)

Deflationism
Iconicity Skeptics

• Eco (1976)

Structuralism
Continuous and discrete structure

• Goodman (1968)
• Sober (1976, 141)

Resemblance

• Peirce (1894) advocated a resemblance theory for images, and an isomorphism theory for diagrams.  (See Sebeok 2001, p. 107 for references.)

First-order isomorphism

• Fodor 2007, Part's Principle (isomorphism of parthood relations under representation)
• Casati and Varzi 1999: map representation follows mereo-topological isomorphism
• Burge

Second-order isomorphism

• Burge
• Kosslyn

Inferentialism

• Shimojima (nomic projection)
• Shin (perceptual cognition)
• Flint (natural generativity)
• Larkin and Simon

Semantic relationalism

• Saussure (arbitrariness and inner connection)