The Arguments in Jean Paul Sartre's Existentialism and Humanism (1)

Jean Paul Sartre had clarified and argued for the theses of Existentialism, and identify it as a sort of humanism. The first principle of Existentialism is that existence came before essence, what it means is that no pre-established a prior human nature determining our decisions in our daily life. Sartre then tried to prove that agent can only follow certain morality in virtue of her own will.

The First Argument:

1. If there is no God, there is no pre-establish a prior human nature which serves as the justification of morality.
2. If there is no God and no pre-established a prior human nature can be given as the base of morality, there is no objective justification for morality.
3. Either people can follow certain morality by justification with the existence of god or human nature, or people can only follow certain morality in virtue of her own will.
4. Therefore, people can only follow certain morality in virtue of her own will.

The Second Argument argued that secular morality can't help:

Assumes that there are objective moral principles, then:

1. All moral principles must be universal principles.
2. No objective way to decide how the universal principles can be satisfied.
3. Therefore, moral agent have to decide by herself how the universal principles can be satisfied.
   

An immediate objection against the above conclusion would be that if morality can't be objectively justified and which can only be appealed to agent's own will, then how one should act would totally depends on agents' subjective will, then what we should do in any particular case would be arbitrary.

Sartre then argued that when an agent chooses for herself, she also chooses for the other. He tried to argue firstly for the claim that, based on the principle that existence came before essence, the essence of a person is what she has done, and constructed the following argument(The Third Argument):

1. The essence of a person is what she has done.
   Let x be a particular person:
   
2. What the agent x chose to do is the one she regarded as that any agents like her should do.
3. What she has done are what she chose to have done.
4. What she has done are the actions she regarded as that any agents like her should do.
5. The essence of x is what she has done.
6. The essence of x is what she regarded as that any agents like her should do.
7. Any particular person is an agent like x.
8. The essence of any particular person is what x regarded as the actions that particular person should do.
9. The essence of mankind is shaped by the essence of any particular person.
10. The essence of mankind is shaped by what x regarded as the actions that any particular person should do.
11. Therefore, x is the legislator of mankind.
12. Since x is can be substituted by any person, therefore, all persons are the legislators of the mankind.
    

Based on the above argument, Sartre can happily claim that our choices of actions are not arbitrary, since we have to be responsible to whole of the mankind, just like an artist have to be responsible to his own painting, although there is no objective rules to guide you to accomplish your works.

Whether "in choosing for himself he choose for all men" means "What the agent x chose to do is the one she regarded as that any agents like her should do." is open to objection. However if we interpret the claim literally, it would be a queer claim that I can decide what the other should do. However, if I can decide how others should act, then either they are not agents like me, or people other than me can't determine their morality with their own will; the former will lead to solipsism and the latter is contrary to the conclusion of the first argument.

Therefore, I tried to interpret the claim as the second premise of the third argument. However, this argument is not invulnerable, as I suspect that I am required to do certain act in certain situation that the action would be best for any people under the similar situation to perform. As under certain Utilitarian principles it may require different people to act differently even they are in similar situation, for maximizing the over-all utility. Sartre may not recognize the objection as a legitimate one as he failed to see how secular morality without positing the existence of God possible. But I think morality without god is possible, and if such a morality is impossible, a morality based on the existence of God is impossible also.

To Be Continued

Some Remarks on Quine's Logic (1)

In his Methods of Logic, Willard Van Orman Quine suggested to test the validity of formulae in Quantificational Logic by transcribing those formulae into Boolean Schemata and applying Truth-value Analysis and ANF. The way he suggested is quite different from the way suggested by I.M Copi in his Symbolic Logic, in which Copi suggested to provide a non-empty model with an normal interpretation to the quantificational schemata in question and test them by using truth-table method.

Moreover, In his Philosophy of Logic, in the chaper about logical truth, he tried to show that any schema-in-L that come out true under all substitution of sentences iff it is satisfied by all models, as long as the language L is reasonably rich, rich enough for elementary number theory, i.e. it can said about positive integers in terms of "+", "*", "=", "↓" and "(x)", but no sets.

The mereological attitude of Quine mentioned above can be explained by his "constructivism" that it is better to posit less on constructing theory.

However it is inevitable to posit sets if we want to simplify the ontology of numbers as set theories provide ways to express arithmetic with following three symbols: "↓", "(x)" and " ∈" and variables such as x, x', x'', x''',....etc., in this way it may be easier to say numbers are only theoretical constructs composed of logical connectives, quantifiers, membership and variables.

A New Place

I think I can't tolerate the interface of Xanga, so I change my blog to here. I would use English here most of the time, but my English is not good, so you may find many mistakes in my articles, and I would try to keep the sentences simple to reduce the chance of making mistake.

I like to read books and articles on Logic and philosophy, and most of the articles in this blog, I expect, would related to these subjects.

I have to go now, see you later.