Is the physical world existing? Descartes takes a thoroughly doubtful attitude to this proposition. He gives much discussion to support this idea at the beginning of his famous book Meditations. George Berkeley redefines the concept of existing in order to respond Descartes’ question in his celebrated writing A Treatise Concerning the Principles of Human Knowledge. How is the connection between them? In this paper I try to reconstruct Descartes’ core argument and introduce Berkeley’s idealism.

一周前，“孤独的阅读者”创始人（船长）在微信朋友圈发了一条信息：

晓莹姐：今天我在万国学院的博尔赫斯的特隆一文讲得格外认真。这是你一年半前重病缠身之际在孤阅讲得第一篇文章。我记得你右手已不能握笔，用左手艰难地写着板书。我那时候知道你想讲什么。我知道你想给学生们留下怎样的哲学财富。你太骄傲了。你的逝去是我们这些教书先生遭遇的最巨大的损失。华人哲学与神学新星就此陨落。这份理想我们会继续传承下去。望你含笑。

我读完后内心十分震惊，一下子难以相信这是事实。原来晓莹老师当时是在处于如此艰难的情况下为学生们讲课，恍然大悟为何老师上课所写板书会较为混乱，而她当时给出的理由却在自嘲：“唉，好久没写中文，这字不行了。”另外，可能近年来发生在自己身边不少亲友和长辈的悄然逝去，让我容易对离别之事产生伤感和哀伤的情绪，慢慢也体会到自己的人生已迈入一个新的阶段，“珍重”一词变得格外响亮和深刻。

Intuitively, it seems to be reliable to the statements as following. If having observed decades of lions that eat meat, we may readily infer that all the lions eat meat. If already heeding that some leaves on trees fall down when the wind flaps each time, we would also hold that the leaves will fall down if the wind flaps again. If all experiments under the same condition we have made bring out one single result that a ball moves forward after a stick hits it, we seem to obtain a regular pattern as well that the balls will move forward afresh once it is struck by the stick in the equal test afterward.

In the first foregoing case, we may apply an inferential method called induction which roughly says that the observations could be justified for the empirical similarities that are unobserved. In the second and third descriptions, we seem to use a causal inference way called causation which plausibly establishes a relation between the cause and the effect. It seems to be quite obvious and normal for us to believe that those theories are true and thus many opinions formulated from life are based on them.

今年国庆中秋长假宅家，读书几乎成为我的唯一消遣，其中最有感触的一事，就在于我学习了《哲学的故事》（The Story of Philosophy）关于哲学家叔本华（Schopenhauer）章节的内容。基于叔本华的经历和思想过多独特，我决定归纳部分文章里很有意思的内容，以及整理本人一些感想，形成现在的文章。

纵观叔本华，无论是他的人生经历还是哲学思想，都蕴含着“悲观主义”色彩，或者是经历塑造人的思想，同时思想又反过来指引并践行着个体人生，如本书作者威尔杜兰特（Will Durant）在该章节开篇描述叔本华是：“一位深邃的悲观主义哲学家。”在看完一半内容时，我突然想起黄先生讲授社会心理学课程时发出对于人生惨淡的感慨，于是顺其自然地我将此篇公众号文章取名为：“敢于直面惨淡的人生”。