If you're focusing on the idea of representation:
* Literalism: This emphasizes the direct meaning of something, without metaphorical interpretation.
* Plainness: This suggests a lack of figurative language or hidden meanings.
* Realism: This focuses on representing things as they actually are, without embellishment or symbolic interpretation.
If you're focusing on the use of symbols:
* Absence of symbolism: This simply denotes the lack of any symbolic elements.
* Objectivity: This implies a focus on facts and direct observation, rather than interpretations.
If you're focusing on the intention to communicate meaning:
* Meaninglessness: This implies a lack of any deeper significance or intended message.
* Randomness: This suggests a lack of deliberate intention or pattern.
Ultimately, the best antonym for "symbolism" depends on the specific context and what aspect of the word you want to oppose.