杨万里通过阐释《易》中的意、象、言符号系统，生发出“因辞求象，象不能外乎辞，因象求道，道不能外乎象”的意、象、言理论。在其诗学中，这一哲学逻辑得以转换为诗学逻辑，而有“万象毕来”，“意在句中”之论，从而形成内蕴儒家言意传统、结构谨严邃密的诗学体系。“万象毕来”论基于杨万里建构的独特的心物关系，更源于他对自然物象的青睐；他论证并建立了凭借自然现象也窥见事理悔吝、入于道境的逻辑，类推于诗学，通过感发自然物象而进入到审美自由便属水到渠成。“意在句中”论建立在杨万里对事理或意义可以被象与辞表达这一观念之上，将意义通过句子的细致表达与言外之意的生成是并行不悖的，言外之意的存在依赖于辞藻字句的精心结撰。

Illustrating the system of meaning, images, and words from The Book of Changes, Yang Wanli concludes that one should seek images through and within words, and Tao through and within images. Applying this philosophical logic to poetic logic, Yang reaches the conclusion that in that case, wan xiang bi lai (you can see all images in your head), and yi zai ju zhong (what you intend to convey has been expressed in sentences) help form rigorously structured poetics with Confucian tradition of meaning and words. Based on Yang's unique theory of mind-material relationship and his favor to natural imagery, wan xiang bi lai theory proves that arcane logic and Tao can also be grasped. As for poetics by analogy with that theory, naturally, natural imagery can lead people toward aesthetic freedom. The theory yi zai ju zhong is based on Yang's conception that reason and meanings can be expressed by images and words. Explicit and implicit meanings can be expressed exquisitely in one same sentence, if the latter derive from elaborate wording and sentence-making.