signs are forms of communication, pointing to something, but symbols go much deeper
a symbol contains in itself something of what it represents
for example, the American flag contains in itself the sense of pride and dignity of being American.
symbols can die or change their meaning, and they may not be meaningful for everyone.
god is the meaning behind all that exists
he cannot be known in a personal way but only through symbols
god is 'being-itself' rather than a being
like poetry, art and music, religious symbols 'speak' to a believer and arouse emotions
the meaning transcends the actual thing
for example, paintings of the secret heart for catholics
as with secular symbols, religious ones don't have meaning for all believers
for example, paintings of the secret heart would leave protestants unaffected or possible offended
symbols both affirm and negate god
they affirm something positive about god
but they also negate that statement because human language is totally inadequate as a description of god.
strengths
avoids the danger of anthropomorphism while allowing believers to experience a deep sense of meaning in their lives through the use of symbol
permits the use of one literal statement about what is meant by 'god' without the need for metaphysical concepts
it reflects what is known through religious experience and so helps us to understand what is meant by sin, salvation, the kingdom of god, etc. symbols surface from the unconscious mind, not from conscious thought.
weaknesses
Tillich's idea of symbols participating in reality is not at all clear, even to some philosophers, let alone to ordinary people
the abstract concept of god as 'being-itself' is not held by most christians, who think in terms of god as a separate and transcendent being. this is true also for deism and process theology
many of the most important things that people want to say about god come from the rational thought and debate of philosophers.