One living philosopher that I can recommend is a professor from UC Berkeley named John Searle. He is an analytic philosopher that has done a lot of work on the issues of philosophy of mind, philosophy of language, and philosophy of society. I am currently listening to his recent lectures at Berkeley via iTunes U. I own one of his books and I ordered another one which I expect to arrive today. The new book I ordered is The Construction of Social Reality. He has some insights that I find both convincing and fascinating. I will briefly summarize one of his insights here using my own visual interpretation of his views and add some of my own insights as well. One important distinction of reality is the difference between objectivity and subjectivity. Objectivity describes that which is the same for everyone. Subjectivity describes that which is different for everyone.
In one of Searle's latest books Making the Social World: The Structure of Human Civilization, Searle poses a fascinating question:
"We make statements about social facts that are completely objective—for example, Barack Obama is president of the United States, the piece of paper in my hand is a twenty-dollar bill, and so on. And yet, though these are objective statements, the facts corresponding to them are all created by human subjective attitudes. ...How is it possible that we can have factual objective knowledge of a reality that is created by subjective opinions?"
One of Searle's favorite examples is money. Money only exists(objectively) because we believe it exists(subjectively). To rephrase his question, how can observer-relative objective facts arise from observer-independent facts of reality? Below is one real world application of the question:
Searle unravels this paradox by identifying a distinction between epistemic and ontological modes of existence. Don't be intimidated by the fancy words. Epistemic simply means pertaining to knowledge. Ontological means pertaining to existence. The question of social facts seems paradoxical because the objective/subjective distinction doesn't account for ontological and epistemic dimension. For example, The belief that Rembrandt was born in 1606 is an epistemically objective fact while the belief that Rembrandt is better than Rubens is an epistemically subjective belief. Here is a visual example of the distinction:
The epistemic objectivity of the statement that Rembrandt was born in 1606 arises from facts about the ontological existence of Rembrandt. The epistemic statement corresponds to reality. The statement of Rembrandt's birth is justified because of observer-independent fact of reality. The diagram below shows the correspondence theory of truth.
But when it comes to social facts such as money, the connection is different. The ontologically subjective belief in money leads to the epistemically objective fact that a particular piece of paper is worth $1.
The important thing to emphasize is that such social institutional facts can be epistemically objective even though human attitudes are part of their mode of existence. That is, observer relativity implies ontological subjectivity but ontological subjectivity does not preclude epistemic objectivity.
Searle attempts to explain how observer-relative objective facts arise from observer-independent features of reality. I will just briefly mention some of the conditions that Searle thinks are necessary to create observer-relative objective facts. These conditions include Language, collective intentionality, and status functions. A common language allows us to exchange ideas and thoughts about reality and make decisions together. Collective intentionality roughly means that multiple people agree on something at the same time (Its actually much more complicated than that. A status function means that we assign a purpose to an object. We don't discover functions in reality, we assign functions to objects. Status functions are the glue that holds human society/civilization together. So in the case of money, we use language and intentionality to collectively assign the function of money to pieces of paper.
Searle also develops the logical form of social facts. He argues that all social facts have the logical form X counts as Y in context C. I will list a few applications that show the logical form. This piece of paper (X) counts as $1(Y) in the United States (context C). Barack Obama counts as the president of the United States. Such and such a move in chess counts as a legal knight move. The fascinating part of this logical structure is that it can iterate upward indefinitely. For example, such and such a sentence in English can count as making a promise, and uttering such and such a promise counts as undertaking a contract. Or, Professional chess players can play blind chess where they don't even need an object in reality to assign a function. They can assign functions to mere thoughts about things that have functions. Wow!
I find this line of thought very interesting and I will continue to explore in writing how observer-relative facts relate to the observer-independent facts.
(new account, not enough rep to comment reply to Michael's follow up question)
There are four apples and therefore the objectively correct answer is four. The third observer is wrong to claim there are 5 apples when there are four. Of course, it might be that there really are 5 apples and that the third person is correct and the first two wrong. Another possibility is that they are all wrong and there are six apples. Regardless, this is a situation where there is one correct answer.
The subjective question is about personal taste. Since it is about taste there is no conflict inherent in having different answers to the question. It is a known property of humans that they differ in their tastes. The question "Is the cake yummy" really should not be taken literally that way. The question is actually reinterpreted by people to me "Do YOU find the cake yummy". Which when asked of different people will generate multiple objective questions, one for each person.
In this case lets call the girl Sue and the boy Joe. The subjective question, "Is it yummy" converts into two objective questions, "Is it yummy for Sue" and "Is it yummy for Joe". The respective answers are yes and no. If Joe were to turn to sue and say "No it is not yummy" then he could be making one of two mistakes. He is either claiming that Sue thinks the cake is not yummy. In which case he is wrong. Or, he thinks that Sue was claiming the cake was yummy for everyone and was disputing that because he doesn't like it. Depending on what Sue meant he could be right or wrong, but only about his interpretation of what Sue was saying. After all if Sue meant it was yummy for everyone she is objectively wrong.
Another distinction that can be made is whether something is metaphysically or epistomologically subjective or objective. Metaphysically objective things are things we call can see. For example the apples. Things that exist in the real world independent of any one person. Metaphysically subjective things are that which only each person experiences and can verify against each other. Exactly how Joe experiences the taste of the cake is not something Sue can experience nor directly verify. This is usually referred to as qualia. This exists in the real world but only to a single person.
Hallucinations are metaphysically subjective and NOT metaphysically objective. That is they exist subjectively but not out in the real world. Metaphysics is about what exists. Certainly hallucinations exist, and the objects of the hallucinations don't exist or they wouldn't be hallucinations.
When speaking epistomologically we are talking about truth claims. Those truth claims that can be decided by metaphysically objective facts are epistomologically objective. Those claims that can be decided by metaphysically subjective facts are epistomologically subjective. The statement "There are four apples" is something all parties can determing by counting. The statement "This cake is yummy" is something that is determined subjectively by tasting it.
I could tell if my cat finds foods yummy by whether she eats them. That's an objective standard for measuring a subjective experience.