In my view, here it is essential to pause and distinguish two different theses: (1) The primary target of semantic theory are linguistic practices (aka language games).
I would like to thank people whose comments on earlier versions of the paper have helped me to improve it in an essential way: Hans Kamp, Pavel Materna, Barbara Partee and Petr Sgall.
For Aristotle it was essential in men to be rational, accidental to be two-legged.
Thus from the point of view of the doctrine of meaning it makes no sense to say of the actual individual, who is at once a man and a biped, that his rationality is essential and his two-leggedness accidental or vice versa.
After this I inquired in general into what is essential I to the truth and certainty of a proposition; for since I had discovered one which I knew to be true, I thought that I must likewise be able to discover the ground of this certitude.
We can say the visual field has certain internal properties, but its being mine is not essential to its description.
That one can see a chair is essential to the meaning of the word.
Freud thinks it is part of the essential mechanism of a joke to conceal something, say, a desire to slander someone, and thereby to make it possible for the subconscious to express itself.
The difference between a reason and a cause is brought out as follows: the investigation of a reason entails as an essential part one's agreement with it, whereas the investigation of a cause is carried out experimentally.
The aim of this article is to explain some of the essential features of human language, and I will emphasize especially those features of language that relate to human society.