Chapter 1

First we must define the terms ‘noun’ and ‘verb’, then the terms ‘denial’ and ‘affirmation’, then ‘proposition’ and ‘sentence.’

Spoken words are the symbols of mental experience and written words are the symbols of spoken words. Just as all men have not the same writing, so all men have not the same speech sounds, but the mental experiences, which these directly symbolize¹, are the same for all, as also are those things of which our experiences are the images. This matter has, however, been discussed in my treatise² about the soul, for it belongs to an investigation³ distinct from that which lies before us.

As there are in the mind thoughts which do not involve truth or falsity, and also those which must be either true or false, so it is in speech. For truth and falsity imply combination and separation. Nouns and verbs, provided nothing is added, are like thoughts without combination or separation; ‘man’ and ‘white’, as isolated⁴ terms, are not yet either true or false. In proof of this, consider the word ‘goat-stag.’ It has significance, but there is no truth or falsity about it, unless ‘is’ or ‘is not’ is added, either in the present or in some other tense.

1 symbolize   

vt.作为...的象征，用符号代表

参考例句：

• Easter eggs symbolize the renewal of life.复活蛋象征新生。
• Dolphins symbolize the breath of life.海豚象征着生命的气息。

2 treatise   

n.专著；(专题)论文

参考例句：

• The doctor wrote a treatise on alcoholism.那位医生写了一篇关于酗酒问题的论文。
• This is not a treatise on statistical theory.这不是一篇有关统计理论的论文。

3 investigation   

n.调查，调查研究

参考例句：

• In an investigation,a new fact became known, which told against him.在调查中新发现了一件对他不利的事实。
• He drew the conclusion by building on his own investigation.他根据自己的调查研究作出结论。

4 isolated   

adj.与世隔绝的

参考例句：

• His bad behaviour was just an isolated incident. 他的不良行为只是个别事件。
• Patients with the disease should be isolated. 这种病的患者应予以隔离。