符号"fa","fb","fc"只有在如下范围内才是函相和主目："Ko(rb)"、"Ko(pf)"和"Ko(hl)"（注：均为德语词，意义分别为：篮子、脑袋、卷心菜）诸语词也是函相和主目。（因此，诸“主目”"rb"、"pf"、"hl"在其他地方是否还被用作语词了，这不会造成任何区别。）
人们很想说：“为了表达出‘(∃x,y).Φx&Φy’，我们需要2个符号'x'和'y'。”但是，这没有任何意义。为了做到这点我们所需要的东西并不是命题的构成成分，而是比如文具。如下说法同样没有意义：“为了表达出‘(∃x,y).Φx&Φy’，我们需要符号‘(∃x,y).Φx&Φy’。”
“任何数都不可能偶然地拥有性质ε；相反，只是根据其本质它们才拥有它的。”——命题“长有红鼻子的那些人脾气好”与命题“喝葡萄酒的那些人脾气好”即使在如下情况下也并非具有相同的意义：长有红鼻子的人恰恰是喝葡萄酒的人。
Overview
The text has been produced from
distinct pieces written by Wittgenstein during the years 1937-1944 and a
few passages are incorporated in the Philosophical Investigations which
were composed later. He adopts an attitude of doubt in opposition to
much orthodoxy in the philosophy of mathematics.
About Ludwig Wittgenstein
Born: Apr. 26, 1889
Died: Apr. 29, 1951
Regarded as the greatest
philosopher of the 20th century, Wittgenstein was born into one of
the wealthiest and most remarkable families of Vienna. His father
was a leading figures in the Austrian iron and steel industry.
Wittgenstein worked primarily in
logic, the philosophy of mathematics, the philosophy of mind, and
the philosophy of language. The only book that published during his
lifetime, Tractatus Logico-Philosophicus, claimed to solve all the
major problems of philosophy and was held in high esteem by the
anti-metaphysical logical positivists.
