本論文研究的對象是當代科學哲學家沙蒙的因果關係理論。他的理論源自於對科學說明理論的探討，認為韓佩爾所提出的涵蓋律模型並不是良好的科學說明模型。他認為恰當的科學說明應為因果說明，亦即在於找出現象真正發生的原因。根據這個考量，他開始進行因果關係的研究。整體而言，沙蒙的因果理論有兩個特點：物理性的、偶然的；其因果理論同時也是因果實在與非決定論式的；除此之外，他宣稱自己的理論也是經驗主義之下的理論。 沙蒙的理論有兩個主要的敵手──第一個是休謨式的因果難題，第二個是在機率現象中以統計觀點理解機率因果的看法。在這篇論文裡，筆者要進行的工作是介紹沙蒙的理論，並且討論、評估他如何處理上述兩個問題。最後論證：沙蒙對於因果關係的切入點是足以深思的。
他採取過程的本體論，區分因果過程與偽因果過程。前者表示具有傳遞記號之能力的過程，而記號則是物理性的守恆量；當因果過程有交叉而發生交互作用時，會發生守恆量的交換，因而產生新的記號並能在過程中被繼續傳遞下去。換言之，因果關係只有因果過程能展現，而因果過程之判別在於物理性的守恆量。
而在面對休謨式的因果難題時，沙蒙對休謨式因果關係提出新判準─因果過程要有傳遞記號之能力─，並且援引羅素用來解決芝諾之飛矢悖論的在─在理論來論證記號移動之可能。但筆者認為他的解決方案是有問題的，無法同時滿足經驗主義的預設與自己的理論；但沙蒙的理論並不因此而沒有價值。在面對統計觀點的機率因果時，沙蒙攻擊：光是用統計的正相關並不足以定義機率因果。他關注「發生機率很低的事件為何會發生」一事，認為之所以會有機率現象，是因為因果過程本身擁有起因的與機率的秉性，這種秉性會使得過程交叉時可能會發生交互作用，且使得交互作用後的結果並不被決定。
筆者最後論證：沙蒙的理論能使我們更確實掌握因果關係這個概念；而考量科學說明此議題，他的理論對於科學說明而言，相對於其兩大敵營來說是更具說服力的理論。

This thesis is devoted to the exploration of Wesley C. Salmon’s theory of causality. Beginning with his investigation of theories of scientific explanation, he denied that the covering-law model is an adequate model of scientific explanation. Instead, he claimed that an adequate explanation should be a causal explanation. Accordingly, he started to do research on causality. On the whole, there are two main characteristics in his theory of causality: physical and aleatory, and also causal realistic and indeterministic. Besides, he claimed that his theory was an empirical theory. There are two main enemies: first, the Humean problem of causation, and second, the statistical account when discussing probabilistic causality. What I will do in this essay is to introduce Salmon’s theory and evaluate his rebuttal of the two enemies above; at the end, I will argue that Salmon’s view still makes senses.
Based on process ontology, he distinguished between causal and pseudo processes by the method called “mark method.” A causal process has the ability to transmit marks while a pseudo process doesn’t; furthermore, the “mark” means physical conserved quantities. When causal processes intersect and interact, there will be exchange of these conserved quantities so that a new mark which can be propogated would be made. Only causal processes can reveal causation, and the criterion is physical conserved quantities possessed by the process.
When facing the Humean problem of causation, Salmon added a new criterion – the ability of mark-transmitting. He introduced Russell’s at-at theory, which was dealing with Zeno’s paradox of flying arrow, to make sure that marks can move. However, his solution was not complete. He can’t coherently maintain both his empirical assumption and his own theory. But this imperfection won’t be critical to his theory. Secondly, when facing the statistical account of probabilistic causality, he argued that statistical positive relevance doesn’t mean probabilistically causal. What concerned him was the following question: “how can an event occur even its probability is very low?” He mentioned the concept “propensity”, both causal and probabilistic. Propensity is possessed by causal processes; it makes the probabilistic distribution after interaction between causal processes.
Finally, I argue that Salmon’s theory can help us to capture the conception of causality better; moreover, in construing scientific explanation as causal explanation, his theory is more convincing than the ones advanced by his two enemies.

Dowe, Phil, (1992) “Wesley Salmon’s Process Theory of Causality and the Conserved Quantities,” Philosophy of Science 59, 195-216.
_____ (1995) “Causality and Conserved Quantities: A Reply to Salmon,” Philosophy of Science 62, 321-333.
_____ (2000) Physical Causation, New York: Cambridge University Press.
Fetzer, J. H., (1988) Probability and Causality: Essays in Honor of Wesley C. Salmon, Boston: D. Reidel Pub. Co..
Good, I. J., (1961) “A Causal Calculus I,” British Journal for the Philosophy of Science 11, 305-318.
_____ (1962) “A Causal Calculus II,” British Journal for the Philosophy of Science 12, 43-51.
Hempel, Carl, G., (1965) Aspects of Scientific Explanation and Other Essays in the Philosophy of Science, New York: Free Press.
Hume, David, (2000) A Treatise of Human Nature, ed. by David Fate Norton and Mary J. Norton, London: Oxford University Press.
Kistler, Max, (2006) Causation and Laws of Nature, New York: Routledge.
Psillos, Stathis, (2003) Causation and Explanation, Canada: McGill Queens University Press.
Reichenbach, Hans, (1991) The Direction of Time, LA: University of California Press.
_____ (1957) The Philosophy of Space and Time, New York: Dover.
Russell, Bertrand, (1922) Our Knowledge of the External World, London: George Allen & Unwin.
Salmon, Wesley, C.,(1998) Causality and Explanation, New York: Oxford University Press.
_____ (1984) Scientific Explanation and the Causal Structure of the World, New Jersey: Princeton University Press.
_____ (1990) Four Decades of Scientific Explanation, Minneapolis: University of Minnesota Press.
_____ (1971) Statistical Explanation and Statistical Relevance, Pittsburgh: University of Pittsburgh Press.
Suppes, Patrick, (1970) A Probabilistic Theory of Causality, Amsterdam: North-Holland.
Woodward, James, (2003) Making Things Happen. Oxford: Oxford University Press.