In a comment on my post on hypotheticals, Krishnamurthy asked:
When you say “Rationality means that man must instead find principles on which to base his actions “, the question arises about how to arrive at those principles. If he cannot use his intuition, and if he cannot do the complicated expected utility maximization, then he can only arrive at the principles by evaluating the outcomes of his previous actions. But to evaluate he would need some principles to begin with. (on second thought, even to do expected utility maximization, he would need to make some evaluations). how does a human being find the principle to base his actions on ?
I hold that knowledge can never be a-priori. To see why, consider these questions
Does a digital balance know how to measure weight?
Does a computer know how to add numbers?
Does my heart know how to pump blood?
Do my eyes and brain know how to distinguish objects from each other?
Does a parrot that recites 2 + 2 = 4 know that 2 + 2 = 4?
My answer to all these questions would be no. There is no knowledge involved here. Knowledge, in the sense applicable to a human mind, involves the exercise of free will. An entity that does not have free will cannot have any knowledge. It is like a machine that does certain things because that is its nature. Since no exercise of free will can occur before one exists, knowledge cannot be a-priori.
Now consider the human mind. I believe that the mind is built with the capacity to use logic, but not with the knowledge of the laws of logic. This is a subtle point. What I am saying is that the mind has an inbuilt ability to determine whether something makes sense. But active effort is required to use this ability. And further effort is required to identify why it makes sense. Men obviously have been using logic for millenia. But it took Aristotle to identify the laws of logic. The operation of the laws of logic is part of the nature of the mind but the knowledge of the laws of logic is not. It takes active effort to grasp the laws of logic – to realize that when something “makes sense”, it is because that something is consistent with the laws of logic. The faculty that is capable of doing this grasping is reason. Man is born with the faculty of reason. But it is the use of reason that results in knowledge.
Recollect the time when you learnt the truth table for “p AND q” where “p” and “q” are propositions. How did you grasp that the truth table was correct? I did so by substituting actual propositions for “p” and “q” and verifying the values in the truth table. This indicates that knowledge of the truth table was not a-priori but the ability to verify particular propositions was. The truth-table was <i>induced</i> from the ability to verify particular propositions. More importantly, this also indicates that in the absence of any particular propositions, I could not have induced the truth table for “p AND q”. This is another reason that knowledge cannot be a-priori.
The ability to understand and evaluate propositions and to induce principles is inbuilt. If you want to call this ability intuition (I call it reason), I have no problem accepting the validity of intuitions, provided effort is made to express the result of this “intuition” in terms of the laws of logic, observations and any other principles one has already validated. But I don’t think this is what anybody means by intuition. For example, the Merriam Webster dictionary defines intuition as
1: quick and ready insight
2 a: immediate apprehension or cognition b: knowledge or conviction gained by intuition c: the power or faculty of attaining to direct knowledge or cognition without evident rational thought and inference
Note the parts I have emphasized. They all indicate that intuition is knowledge achieved without active effort and without the use of reason.
Does this answer your question?