在書中，Popper 所謂的 'historicism' ﹝歷史定論主義﹞是指「試圖藉找出歷史發展的趨勢或韻律，從而預測未來社會發展」的一門社會科學 ──
An approach to the social sciences which assumes that historical prediction is their principal aim, and which assumes that this aim is attainable by discovering the 'rhythms' or the 'patterns', the 'laws' or the 'trends' that underlie the evolution of history. (p.3)Popper 以邏輯反駁歷史定論主義 ──
1. The course of human history is strongly influenced by the growth of human knowledge[...]── ，指出歷史定論主義者錯誤地將趨勢﹝trends﹞當成全稱定律﹝universal laws﹞ ──
2. We cannot predict, by rational or scientific methods, the future growth of our scientific knowledge[...]
3. We cannot, therefore, predict the future course of human history[...]
4. [...]There can be no scientific theory of historical development serving as a basis for historical prediction.
5. The fundamental aim of historicist methods is therefore misconceived; and historicism collapses.
(p.xii)
[T]he existence of trends or tendencies in social change can hardly be questioned. [...]But trends are not laws. A statement asserting the existence of a trend is existential, not universal. [...]And a statement asserting the existence of a trend at a certain time and place would be a singular historical statement, not a universal law. [...]while we may base scientific predictions on laws, we cannot[...]base them merely on the existence of trends. A trend[...]which has persisted for hundreds or even thousands of years may change within a decade, or even more rapidly than that. [...L]aws and trends are radically different things. (p.106)
Explained trends do exists, but their persistence depends on the persistence of certain specific initial conditions (which in turn may sometimes be trends)[...H]istoricists overlook the dependence of trends on initial conditions[...]Their confusion of laws with trends makes them believe in trends which are unconditional (and therefore general)[...](p.118)── 及將歷史詮釋﹝historical interpretation﹞誤當成理論﹝theory﹞ ──
For in theoretical science laws act, amongst other things, as centres of interest to which observations are related. [...]In history the universal laws[...]cannot possibly fulfil this function. It must be taken over by something else. For undoubtedly there can be no history without a point of view; like the natural sciences, history must be selective[...] (p.138-139)
The only way out[...]is[...]consciously to introduce a preconceived selective point of view into one's history[...A]ll available evidence which has a bearing on our point of view should be considered carefully and objectively. (p.139)
We shall call such a selective point of view[...]a historical interpretation. (p.139-140)
Historicism mistakes these interpretations for theories[...They] do not see that there is necessarily a plurality of interpretations which are fundamentally on the same level of both suggestiveness and arbitrariness. [...]Instead, they present them as doctrines or theories[...] (p.140)── ，並對歷史定論主義﹝尤其是馬克斯主義﹞，以及「烏托邦工程」﹝Utopian engineering﹞作出猛烈評擊，指烏托邦工程只是一場「春秋大夢」﹝an Utopian dream﹞。
在書中﹝§32﹞，Popper 提出 Institutional Theory of Progress ﹝發展的制度理論﹞，否定科學的客觀性並非單純依靠科學家持「客觀」的態度﹝因為態度是個人及內在的，既無法量度，亦難以在人與人之間作比較，根本無「客觀」可言﹞。Popper 認為科學的客觀性某程度上是基於社會制度﹝what is usually called 'scientific objectivity' is based, to some extent, on social institutions﹞，因為科學﹝及其客觀性﹞是建基於思想的自由競爭﹝free competition of thought﹞，須要民主的政治制度來維護 ──
Scientific method itself has social aspects. Science, and more especially scientific progress, are the results not of isolated efforts but free competition of thought. For science needs ever more competition between hypotheses and ever more rigorous tests. And the competing hypotheses need personal representation... This personal representation must be institutionally organized if we wish to ensure that it works. And these institutions have to be paid for, and protected by law. Ultimately, progress depends very largely on political factors; on political institutions that safeguard the freedom of thought: on democracy. (p.143)
If the growth of reason is to continue, and human rationality to survive, then the diversity of individuals and their opinions, aims, and purposes must never be interfered with. [...]Even the emotionally satisfying appealing for a common purpose, however excellent, is an appeal to abandon all rival moral opinions and the cross-criticisms and arguments to which they give rise. It is an appeal to abandon rational thought. (p.147)
Holistic control, which must lead to the equalization not of human rights but of human minds, would mean the end of progress. (p.147)要知《歷史定論主義的窮困》的初稿在 1935 年完成，而 Popper 早在 1919-20 年已意識到歷史是不可預測的 ──
The fundamental thesis of this book ── that the belief in historical destiny is sheer superstition, and that there can be no prediction of the course of human history by scientific or any other rational methods ── goes back to thewinter of 1919-1920. The main outline was completed by 1935; it was first read, in January or February 1936, as a paper entitled 'The Poverty of Historicis'[...](Historical Note)── ；那個時期正值俄國十月革命﹝1917﹞之後、第二次世界大戰爆發﹝1939﹞之前，共產主義的種子正在散播，當時世上不少人對「烏托邦工程」﹝Utopian engineering﹞奉若神明。
參考資料：
- The Poverty of Historicism, Karl Popper, Routledge Classics 2002, ISBN 0-415-27846-5
