當代知識論關於證成性質的討論，內在論與外在論之爭，源自於知識的傳統分析：知識與僅僅是真信念的區別是什麼？根據知識的傳統分析，知識除了真信念之外，還需要再加上好理由，例如足夠的證據或夠強的背景作為知識的第三項條件，也就是證成。但是蓋提爾難題顯示出證成的真信念並沒有辦法避免將幸運猜測歸為知識，於是一些哲學家開始採取不同的進路，指出知識的關鍵，是信念與致真項之間的正確因果連接，這個立場更進一步地發展出可靠論與索真論。上述觀點可以大致區分為「好理由理論」與「因果理論」，粗略來說，兩者即分別對應至「內在論」與「外在論」。直至目前的主流發展，內在論的代表理論是證據論，外在論的代表理論是可靠論。
可靠論遭遇到許多攻擊，其中最被廣泛討論，也最致命的理論困難是「普遍性難題」：可靠的過程所產生的信念即是被證成的信念，但可靠性要如何判斷？可靠論者必須提出挑出「相關類型」的方法才能夠計算可靠度。另一方面，證據論所遇到的主要挑戰是：何謂證據？證據是如何支持信念的？證據論必須提供一個解釋以說明證據以及證據與信念之間的關係，否則會是空的理論。
普遍性難題受到非常多的討論，許多可靠論者皆試圖提出回應，但其背後的深度尚未受到討論。本課程將分析可靠論者對於普遍性難題的回應，並將其區分為三種主要類型：找尋相關類型、迴避回應，以及訴諸認知科學，加以仔細檢驗，並藉由深入討論進一步指出其背後的的問題。
The epistemological debate about justification between internalism and externalism originates from the traditional analysis of knowledge: What distinguishes knowledge from mere true belief? According to the traditional analysis, a true belief has to satisfy a third condition to be qualified as knowledge: there has to be good reason, namely, justification. But the Gettier problem shows that even justified true belief may fail to exclude lucky guess, which has led to some alternative approaches that emphasize the right causal connections such as reliabilism or tracking theories. So we have a division between ‘good reason’ accounts and ‘causal’ accounts, roughly corresponding to internalism and externalism respectively. The main internalist account is evidentialism, and the main externalist account is reliabilism.
Reliabilism has faced many challenges, including the widely discussed ‘generality problem’: How should we determine a ‘relevant type’ so as to calculate reliability? On the other hand, Evidentialism also faces its own challenges: What is evidence? How does evidence support beliefs? Evidentialism needs an account for the relationship between evidence and belief.
The generality problem is widely discussed, and there have been many attempted responses in the literature, but its significance is still not fully appreciated. This course will examine the reliabilist responses to the generality problem: the relevant-type response, the parrying responses, and the responses that invoke cognitive science, and will examine the problems behind these responses.