"Cleanthes (/kliˈænθiːz/; Greek: Κλεάνθης; c. 330 BC – c. 230 BC), of Assos, was a Greek Stoic philosopher and boxer who was the successor to Zeno of Citium as the second head (scholarch) of the Stoic school in Athens. Originally a boxer, he came to Athens where he took up philosophy, listening to Zeno's lectures. He supported himself by working as a water-carrier at night. After the death of Zeno, c. 262 BC, he became the head of the school, a post he held for the next 32 years. Cleanthes successfully preserved and developed Zeno's doctrines. He originated new ideas in Stoic physics, and developed Stoicism in accordance with the principles of materialism and pantheism. Among the fragments of Cleanthes' writings which have come down to us, the largest is a Hymn to Zeus. His pupil was Chrysippus who became one of the most important Stoic thinkers.
Cleanthes was born in Assos in the Troad, about 330 BC. According to Diogenes Laërtius, he was the son of Phanias, and early in life he was a successful boxer. With but four drachmae in his possession he came to Athens, where he took up philosophy, listening first to the lectures of Crates the Cynic, and then to those of Zeno, the Stoic. In order to support himself, he worked all night as water-carrier to a gardener (hence his nickname the Well-Water-Collector, Greek: Φρεάντλης). As he spent the whole day in studying philosophy with no visible means of support, he was summoned before the Areopagus to account for his way of living. The judges were so delighted by the evidence of work which he produced, that they voted him ten minae, though Zeno would not permit him to accept them. His power of patient endurance, or perhaps his slowness, earned him the title of "the Ass" from his fellow students, a name which he was said to have rejoiced in, as it implied that his back was strong enough to bear whatever Zeno put upon it.
Such was the esteem awakened by his high moral qualities that, on the death of Zeno in 262 BC, he became the leader of the school. He continued, however, to support himself by the labour of his own hands. Among his pupils were his successor, Chrysippus, and Antigonus II Gonatas, from whom he accepted 3000 minae. He died at the age of 99, c. 230 BC. We are told that a dangerous ulcer had compelled him to fast for a time. Subsequently he continued his abstinence, saying that, as he was already half-way on the road to death, he would not trouble to retrace his steps.
Simplicius, writing in the 6th century AD, mentions that a statue of Cleanthes was still visible at Assos, which had been erected by the Roman Senate.
Cleanthes revolutionized Stoic physics by the theory of tension (tonos) which distinguished Stoic materialism from all conception of matter as dead and inert. He developed Stoic pantheism, and applied his materialistic views to logic and ethics. Thus he argued that the soul was a material substance, and that this was proved by the circumstance that not only bodily qualities, but also mental capacity, are transmitted by ordinary generation from parent to child; and by the sympathy of the soul with the body seen in the fact that, when the body is struck or cut, the soul is pained; and when the soul is torn by anxiety or depressed by care, the body is correspondingly affected. Cleanthes also taught that souls live on after death, but that the intensity of its existence would vary according to the strength or weakness of the particular soul.
Cleanthes regarded the Sun as being divine; because the Sun sustains all living things, it resembled the divine fire which (in Stoic physics) animated all living beings, hence it too must be part of the vivifying fire or aether of the universe. Some maintain that he accused Aristarchus of impiety for daring to put into motion "the hearth of the universe" (i.e. the Earth); this interpretation depends on an emendation of the received text, since in the manuscripts it is Aristarchus that did the accusing. The largest surviving fragment of Cleanthes is the portion of the Hymn to Zeus, which has been preserved in Stobaeus, in which he declares praise and honour of Zeus to be the highest privilege of all rational beings."
克里安西斯（Cleanthes；古希臘語：Κλεάνθης；約公元前330年－前230年），阿索斯人，是一位希臘斯多葛哲學家及拳擊手，在芝諾．奧菲提烏姆去世後成為斯多葛學派在雅典的第二任學派領袖（學派首領）。克里安西斯最初是一名拳擊手，後來來到雅典聽芝諾的講座而轉向哲學研究。他靠著夜間擔水維生。芝諾約於前262年去世後，他成為了學派的頭目，這一職位他保持了接下來的32年。克里安西斯成功地保留和發展芝諾學說。他在斯多葛物理學中提出了新的觀點，並根據唯物論和泛神論的原則，對斯多葛主義進行了發展。
傳至我們這裡的克里安西斯著作的片段中，最大的一部分是一首《讚頌宙斯》的頌歌。他的學生克里西普斯成為了斯多葛思想中最重要的人物之一。
克里安西斯生於特洛伊地區的阿索斯，約公元前330年。根據狄奧根尼斯．拉爾提烏斯的記載，他是Phanias的兒子，早年是一位成功的拳擊手。帶著僅有的四德拉克馬，他來到雅典，先是聽了犬儒學派的克拉底斯的講座，然後才聽芝諾的斯多葛講座。為了維生，他整夜作為園丁的擔水工工作（因此有“井水搜集者”（希臘語：Φρεάντλης）的綽號）。由於他整天都在學習哲學，但看起來沒有明顯的維生手段，因此被召喚到阿雷奧帕古斯法庭說明他的生活方式。法官對他展示的工作證據感到非常高興，他們投票給了他十個米納，儘管芝諾不允許他接受這些錢。他的耐力或許表現在他的遲緩上，使他從其同學那裡獲得了“驢子”之稱，他據說對此感到高興，因為這意味著他的背膀足夠堅強，能夠承擔芝諾賦予在他身上的任何東西。
由於克萊安西斯高尚的道德品質激起了極高的敬意，故在芝諾於前262年逝世後，他成為了該學派的領導者。然而，他持續依靠自己的雙手勞動來支撐生活。他的學生包括他的繼任者克里西普斯以及安提柯努斯二世，他接受了安提柯努斯贈予的三千米納。克里安西斯於約前230年以九十九歲的高齡逝世。據說一個危險的潰瘍迫使他暫時禁食。後來，他繼續保持節制，說他已經走到了死亡之路的一半，就不會再麻煩回頭了。在公元6世紀時，西姆普利希烏斯提到，克萊里安西斯在阿索斯仍可見其雕像，是由羅馬參議院所立的。
克里安西斯通過張力（tonos）理論使斯多葛物理學發生了革命，該理論使斯多葛唯物論與所有對物質為死物和遲鈍的概念區分開來。他發展了斯多葛泛神論，並將他的唯物論觀點應用於邏輯學和倫理學。因此，他辯稱靈魂是一種物質實體，這一點從身體品質和精神能力通過普通世代從父母傳遞給孩子的事實得到證明，以及從當身體被擊打或割傷時靈魂感到疼痛的現象中可見靈魂與身體的共感；以及當靈魂被焦慮撕裂或被憂慮壓垮時，身體也相應受到影響。
克里安西斯還教導說，靈魂在死後會繼續生存，其存在的強度會根據特定靈魂的強弱而有所不同。克萊恩西斯認為太陽是神聖的；由於太陽維持著所有生物的生存，它類似於在斯多葛物理學中激發所有生物的神聖火焰，因此它也必須是宇宙中滋養生命的火焰或乙太的一部分。有人認為他因敢於使“宇宙的爐龕”（即地球）運動而指控阿里士塔克斯不敬；這種解釋取決於對收到的文本的修改，因為在手稿中是阿里士塔克斯進行了指控。保存下來的克里安西斯最大的片段是讚頌宙斯的部分，斯托貝奧斯保存了這部分，在其中他宣稱讚美和尊崇宙斯是所有理性生物的最高榮譽。
"Lead me, Zeus, and you too, Destiny,
To wherever your decrees have assigned me.
I follow readily, but if I choose not,
Wretched though I am, I must follow still.
Fate guides the willing, but drags the unwilling."
引領我吧，眾神之父－宙斯，命運，亦同，
帶我前往我早已命定的地方。
我甘願遵循，即便我抗拒，
即使我悲慘，我仍舊必須遵從。
命運引導著祈願者，卻拖拽著不違抗者。