就具體個案因果關係之證明而言，吾人首先須以經驗法則、或科學實證資料與統計數據等，建構出該類案件整體性的「抽象因果關係」，而後方能將個案情節與之比照，判定「個案因果關係」，作為損害賠償歸責之基礎。惟新類型侵害案件之因果機轉已逸脫吾人現有抽象因果關係之認知範疇，致使個案因果關係無從比照，而發生論斷之困難，就此，日法學界遂有「疫學手法」之倡議。惟援用「疫學手法」之中、日判決，仍有不少可議之處，導致該手法適用之正當性與正確性迭遭學者強烈之質疑與批評。 本文以因果關係之邏輯結構與證據法則切入，闡明「疫學手法」於因果關係論證上之作用與機能即在於，就無前經驗性之損害案件進行實時間之疫學調查，並以「疫學四條件」寬鬆地建構其集團性抽象因果關係。而所謂疫學四條件之審查，其實已滿足因果關係命題最基本之充要邏輯性要求，倘再能精確地掌握「疫學手法」之無前經驗性與集團性等特性，即可避免其適用上之缺失。於我國現行法制下，藉由「疫學手法」、民事訴訟法第281條、同法第277條但書規定、以及民法第191條之3等之妥善運用，除可緩和該類案件被害人舉證之困難，增加其實體法權利實現之可能性外，另一方面，對可疑之加害人提供了可反證免責之程序保障，亦不至於太苛。果爾，應可充實我國侵權行為損害賠償體系之內涵，此於新類型損害層出不窮之今日，實具有格外重要之意義。

In the contemporary or near future juridical context, scientific uncertainty may arise in the causal inquiry more frequent than ever, especially in the rising litigations of environmental, toxic, pharmacologic, irradiational, electron-magnetic or even biogenetic technologic torts…etc. accompanied by the tremendous improvements to our modern way of life. In such litigations, establishing the causation connection between the alleged causes and the injuries complained of is probably the most difficult task. The scientific uncertainty will certainly result in the experts' inability to provide an exact answer to the causal inquiry or in the dispute among them, which will inevitably build up the evidence gap and eventually prevent the plaintiff from discharging his burden of proving causation. With the attempt to relax the strict traditional causation test in scientifically uncertain cases, the Japanese jurisdiction has accordingly advocated 5 decades ago the ”Epidemiologic Causation Theory”-As long as the epidemiologic evidence meets all the requirements of consistency, strength, temporal relationship, and coherence, then the causation between the observed alleged cause and the injury is established or highly implied. This article elaborated the Theory fundamentally with special emphasis on its theoretic and practical aspects and holds that the ”Epidemiologic Causation Theory”, by utilizing the real-time epidemiologic statistic analysis, actually exhibits itself merely as a preliminary epidemiologic observation on the possible association (not causation) between the suspected alleged causes and the injuries, which, as a relaxing remedy, functionally served as ”general causation” or ”abstract causation” in causal inquiring process. Consequently it is definitely mandatory to further confront this ”abstract causation” against the possibility that the damage was caused by other factors in individual case under litigation to establish the sound and concrete ”personal causation”. Only when the ”Epidemiologic Causation Theory” is properly applied, can the fairness and justice of jurisdiction finally be realized.