朱子之鬼神論乃其宇宙觀之重要部分，亦為其建構儒家政治社會倫理秩序及批判佛家輪迴因果說之重要基礎。其說既非無神論，又非人格神論，而具有統合神靈、精神、物質與人生界之特性。其體系複雜，中含種種看似矛盾之處，是以頗滋疑義。本文將本於朱子超越心物二元、主體與非主體對立之「生命化」暨「一體化」之氣化宇宙觀，對其鬼神論做出疏釋。
朱子以鬼神之事本屬難知，人當深察於造化之可知而後及於其所難知。朱子即天地陰陽變化之妙而名之以鬼神，其眼中之造化，處處有理，亦同時為一處處「含生」、神妙感通之宇宙。其中天神與地祇乃天地山川之靈。人鬼則為人死後未消盡之魂魄。朱子承認上帝，然強調其自然義。雖信神仙與佛門多神異，然不信不壞之仙佛及輪迴。其所謂之鬼神，常在若有若無之間。
朱子之說上接先秦較人格化之鬼神觀，下承宋儒之自然氣化觀，中而參究民間經驗傳說。其所愛重，是為清明而衡平之古禮世界，將鬼神還諸天地造化之公。其所對應，則為自然界與神靈界合一之儒道傳統觀點。至於其上帝即理說暨批判人格化鬼神說，則深具近世精神。如此之鬼神論，可使生民敬畏天地神明，崇祀祖先，並以自然人情為本，無怖於鬼神與生死，在歷史上深具意義。

Zhu Xi’s 朱熹 theory of ghostly and godly existence is a basic part of his cosmology. It forms the foundation of his refutation of the Buddhist theory of reincarnation, and is a building block of his socio-political and ethical theories. Zhu Xi is neither a theist nor an atheist. This seemingly contradictory attitude makes his thought difficult for scholars to understand. This paper seeks to interpret Zhu Xi’s theory from his organismic and holistic world view, which transcends the dichotomy between idealism and materialism and the gulf between the subjectivity and non-subjectivity of things. Zhu Xi believes that the world of ghosts and gods is hard to know, and insists that we should start from what we know about the nature of this world so as to reach a better understanding of the more mysterious part of the world. He considers the world to be the product of the flow and evolution of qi 氣 (air/mass), which amasses and dissipates all the time. He uses yin-yang 陰陽 to describe the amassment and dissipation of qi, and the terms ghostly and godly to describe the marvelous function of yin-yang. In his eyes, the universe is led by lively “rationales/patterns” that can create wonders and even ghostly and godly existence. He then uses this theory to interpret all kinds of wonders and the socalled world of gods and ghosts.