Improving Chain-of-Thought Reasoning via Quasi-Symbolic Abstractions

Leonardo Ranaldi, Marco Valentino, Andre Freitas


Abstract
Chain-of-Though (CoT) represents a common strategy for reasoning in Large Language Models (LLMs) by decomposing complex tasks into intermediate inference steps. However, explanations generated via CoT are susceptible to content biases that negatively affect their robustness and faithfulness. To mitigate existing limitations, recent work has proposed using logical formalisms coupled with external symbolic solvers. However, fully symbolic approaches possess the bottleneck of requiring a complete translation from natural language to formal languages, a process that affects efficiency and flexibility. To achieve a trade-off, this paper investigates methods to disentangle content from logical reasoning without a complete formalisation. In particular, we present QuaSAR (for Quasi-Symbolic Abstract Reasoning), a variation of CoT that guides LLMs to operate at a higher level of abstraction via quasi-symbolic explanations. Our framework leverages the capability of LLMs to formalise only relevant variables and predicates, enabling the coexistence of symbolic elements with natural language. We show the impact of QuaSAR for in-context learning and for constructing demonstrations to improve the reasoning capabilities of smaller models. Our experiments show that quasi-symbolic abstractions can improve CoT-based methods by up to 8% accuracy, enhancing robustness and consistency on challenging adversarial variations on both natural language (i.e. MMLU-Redux) and symbolic reasoning tasks (i.e., GSM-Symbolic).
Anthology ID:
2025.acl-long.843
Volume:
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Wanxiang Che, Joyce Nabende, Ekaterina Shutova, Mohammad Taher Pilehvar
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
17222–17240
Language:
URL:
https://preview.aclanthology.org/ingestion-acl-25/2025.acl-long.843/
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Bibkey:
Cite (ACL):
Leonardo Ranaldi, Marco Valentino, and Andre Freitas. 2025. Improving Chain-of-Thought Reasoning via Quasi-Symbolic Abstractions. In Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 17222–17240, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
Improving Chain-of-Thought Reasoning via Quasi-Symbolic Abstractions (Ranaldi et al., ACL 2025)
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https://preview.aclanthology.org/ingestion-acl-25/2025.acl-long.843.pdf