Few Americans know that Charles Saunders Peirce ("purse") is our greatest philosopher, our greatest 19th century mathematician and logician, the planner of The Bureau of Standards, and the creator of Semiotics: Theory of Signs. And few know that this great man died of malnutrition. (Texts and reference books often write more about the independent semiotics ideas of French scholar, Ferdinand Saussure (x-y). I build upon Peirce's work since they give me a geenratic basis and Saussure's does not.)

I formulated an acronym, "ISIS", for what I consider the four primary signs which Peirce taught us.

I(ndicator)S(ignal)I(con)S(ymbol).

INDICATOR Extending Peirce, I redefine
INDICATOR: ORDERED PAIR OF SIGNS: THE 1st IS HIGHLY VISIBLE, LOW IN INFORMATION CONTENT; THE 2nd LOW IN VISIBILITY, HIGH IN INFORMATION CONTENT.
(Examples: LIGHTNING INDICATING THUNDERSTORM; LITMUS PAPER TURNING RED, INDICATING LIQUID ACID IN TEST TUBE.

SIGNAL Extending Peirce, I redefine
SIGNAL: INDICATOR UNDER PHYSICAL AND LINGUISTIC CONTROL.
(Peirce mentioned only PHYSICAL CONTROL.) Example: TELEGRAPHIC SIGNAL -- under PHYSICAL CONTROL OF ELECTRIC CIRCUIT AND BREAKER KEY; under LINGUISTIC CONTROL OF MORSE CODE.)

INDICATOR-SIGNAL STRATEGY: THE GOAL OF SCIENCE IS TO SEARCH FOR SIGNALS AND TRY TO TRANSFORM INTO SIGNALS!

This can be seen in a Table of Indicators and SIGNALS.

ICON An ICON IS A SIGN THAT SUGGESTS OR INVOKES ITS MEANING OR REFERENCE.
Examples: "No Smoking!" ICONED as CIGARETTE WITH SLASH THROUGH IT; ONOMATOPOEIC WORDS; etc.

SYMBOL A SYMBOL IS A SIGN WITH ARBITRARILIY ASSIGNED MEANING OR REFERENCE.

(An ICON is HIGHLY VISIBLE, but with LIMITED MEANING OR REFERENCE. A SYMBOL has LOW 'VISIBILITY", BUT UNLIMITED INFORMATION CONTENT.)

ICON-SYMBOL STRATEGY: THE GOAL OF LITERACY IS TO MAKE THE ICON A BRIDGE TO THE SYMBOL.