本文从亚里士多德的“海战”问题出发，站在非决定论的立场，研究关于将来不确定性的两个问题。一是重新对将来偶然命题的真值进行思考，给予其一种假设解释；二是进一步关心一类特殊的将来偶然事件，即“意外”。“意外”的特殊在于它不仅涉及将来的不确定性，同时它还是一个具有主观色彩的概念，涉及一个具体的主体。我们需要明确一个将来偶然事件的发生在什么情况下对某个主体来说是一个“意外”。
       本文将分为三大部分对这两个问题展开研究。第一部分包括第1章 和第2章，是对于一些关于将来的基础性问题的探讨。第1章基于“海战”问题，首先说明事件的时态特性（过去性、现在性、将来性）是相对于某一个具体的时刻而言的；其次强调世界在时间维度上是一个分支结构，以表示过去和现在的不可更改性和将来的不确定性，而时间本身具有的是线性结构；最后表明无论是时态命题还是非时态命题，由于它们都能够反映事件的时态特性，所以我们需要在一个具体时刻上谈论其真值。第2章进一步对关于时态命题真值条件的争论展开讨论。在时态理论的基础上，用来定义时态命题的双向条件句的左边是使我们能够谈论命题真值的语境，右边作为真值条件是命题描述的真实发生的事件。此外，当我们定义时态命题的真值时，真谓词同样具有时态性质（过去为真、现在为真、将来为真）。
本文的第二部分，即第3章是研究的重点内容之一，提出了对将来偶然命题真值的一种假设——更新解释。我们将时态命题的真值划分为假设真值和确定真值，将真的外延划分为确定外延和假设外延。相应的，在具有分支结构的时态逻辑中给出了确定模态词和假设模态词。与必然模态词和可能模态词不同，它们是在语境的基础上考虑这个语境的所有可能将来，而必然和可能模态词是在世界的基础上考虑所有语境的所有可能将来。基于此，我们进一步在分支结构的时态模型上给出时态命题的真值定义，以及对亚里士多德在“海战”问题中所说的必然性进行解释。
第三部分在前面两部分的基础上转向对“意外”这类特殊的将来偶然事件的研究，是本文的重点内容之二，包括第4章和第5章。第4章从一个涉及“意外”的经典悖论（意外考试悖论）出发对“意外”进行哲学上的探讨。从主体的认知和心理预期两个角度可以对“意外”做两种区分，并且可以在弱意义上和强意义上对其做进一步的区分。弱“意外”指的是主体在某个时刻不知道（或不预期）将来某件事将会发生而这件事实际上发生，强“意外”则表示主体在某个时刻知道（或预期）将来某件事的发生而这件事实际上不发生。其中，定义“意外”的关键在于明确主体的认知或心理预期发生的具体时刻。意外考试的产生源自学生关于将来考试时间的不确定性，所以我们在弱意义上分别从认知和心理预期对其做了重新的解读，表明学生对“意外”的错误解释是悖论产生的根源。由于知识的性质以及“意外”所涉及的将来因素，第5章在心理预期层面上讨论“意外”并且进一步给予一种形式解释。心理预期对应的是主体的信念，因而在时态信念修正模型的基础上，我们提出一种基于分支结构的时态信念更新模型，给予预期和不预期、强“意外”和弱“意外”以严格的定义，并且对它们的一些事实和性质进行了证明。基于“意外”的定义，进而在时态信念更新模型中对意外考试悖论进行形式解释，从“意外”的角度给予悖论一种新的解决方法。

Starting from Aristotle's "Sea Battle" and taking an indeterministic standpoint, this thesis studies two issues concerning the future uncertainty. One is to rethink the truth-value of future contingents and give it a hypothetical explanation. The second is to pay more attention to a special type of future contingency, namely "surprise".The special of "surprise" is that it not only involves the uncertainty of the future, but it is also a subjective concept involving a specific agent. We need to be clear that under what circumstance a future contingency will be a "surprise" for an agent.
This thesis will be divided into three parts to study these two issues. The first part includes Chapter 1 and 2, which is a discussion of some basic questions about the future. Based on the issue of "Sea Battle ", Chapter 1, firstly, explains that the temporal characteristics of events (pastness, presentness, and futureness) are relative to a specific moment. Secondly, it emphasizes that  to represent the immutability of the past and present and the uncertainty of the future, the world is a branching structure in terms of  the time dimension, and time itself has a linear structure. Finally, it shows that whether it is a tensed proposition or a tenseless proposition, it can reflect the temporal characteristics of the event so that we need to talk about its truth-value at a specific moment. Chapter 2 further discusses the controversy about the truth condition of tensed proposition. On the basis of tensed theory, the left side of a  biconditional sentence used to define the tensed proposition is a context in which we can talk about the truth-value of the proposition, and the right side as the truth condition is the real occurrence of the event described by the proposition. In addition, we cannot ignore the tensed nature of the truth predicate when we define the tensed proposition's truth.
As the second part of this thesis, Chapter 3 is one of the key contents of this article. This part puts forward a hypothetical-updated interpretation of the truth-value of the future contingents. We divide the truth-value of the tensed proposition into hypothetical and definite truth-value, and  the true extension into hypothetical and definite extension. Correspondingly, the definite modal term and the hypothetical modal term are given in the temporal logic with a branching structure. Unlike the necessary modal term and the possible modal term, which consider all possible futures of all contexts on the basis of some world,  the definite one and the hypothetical one consider all possible futures of some certain context. Based on this, we further give the truth definition of the tensed proposition, and explain the necessity of Aristotle's "Sea Battle" in the temporal model  with a branching structure.
On the basis of the previous two parts, the third part turns to the study of a special future contingency, "surprise", which is the second key content of this article, including Chapter 4 and  5. Chapter 4 starts with a classic paradox (surprising exam paradox) involving "surprise", and carries out a philosophical discussion on "surprise".  From the perspective of the agent's cognition and psychological expectation, two types of "surprise" can be distinguished, and they can be further distinguished from the weak sense and the strong sense. A weak "surprise" means that some agent does not know (or does not expect) that something will happen in the future at a certain moment and it actually happens. A strong "surprise" means that the agent knows (or expects) at a certain moment that something will happen in the future and this will not actually happen. Among them, the key to defining "surprise" is to clarify the specific moment when the agent's cognitive or psychological expectations occur.The emergence of surprising exam stems from the uncertainty of the future exam time, so we reinterpret it from the cognitive and psychological expectation in a weak sense, indicating that student's misinterpretation of "surprise" is the root of the surprising exam paradox. Due to the nature of knowledge and the future factors involved in the "surprise", Chapter 5 discusses "surprise" at the level of psychological expectation and further gives it a formal explanation. Psychological expectation corresponds to the belief of the agent. Therefore, on the basis of the temporal belief revision model, we propose a branching structure-based temporal belief update model, which gives expectation and non-expectation, strong "surprise" and weak "surprise"  strict definitions, and proves some facts concerning them. Based on the definition of "surprise", we formally explain the paradox of surprising exam in the temporal belief update model, and give the paradox a new solution from the perspective of "surprise".