Are there rules of thinking? There seems to be some sort of identifiable order to the material world, as evidenced by the laws of physics, biology, etc. However, do we have any reason to believe that similar laws might exist for the immaterial realm of thought?
As thorny as some of the above questions might seem, they all implicitly contain their own answer. Are there rules of thinking? Well, either there are or there aren't -- that's the logical law of excluded middle. Even the second question assumes that we should look for a reason or evidence that such laws exist; it assumes that reason can lead to knowledge. The existence of at least some order or rules to thinking seems unavoidable. What's more, we know we had nothing to do with making these rules any more than we had anything to do with creating the gravitational force or the replication mechanism of DNA. The fact the we discovered them doesn't mean we created them any more than the fact that you're reading the words on this blog means that you wrote them. That being the case, logic is not something that we arbitrarily made, but something that we discovered. When you walk through a building and slam into a wall because you didn't look where you were going, you know you didn't put that wall there. My experience with logic has been like running into a mental wall; I know I didn't put it there, and there seems to be no way around it.
Before getting to the (rather simple) basic laws of logic, it would be useful to have a working definition of logic itself. Informally defined, logic is a way to think so that we can come to correct conclusions by understanding implications and the mistakes people often make in thinking. (Geisler and Brooks, CLR) Logic is a prerequisite of all thinking. Without the order of logic, no thought would be possible, no argument would ever even begin to get off the ground. Even those who wish to deny logic cannot avoid using it in that very denial. For lack of a better phrase, logic is so inescapable that it seems to be built in to the very fabric of the universe.
The three fundamental laws of thought are:
1) The law of noncontradiction (A is not non-A)
2) The law of identity (A is A)
3) The law of excluded middle (either A or non-A)
Well, those are all well and good, and no one denies that Aristotle guy was pretty sharp, but why should anyone accept these laws? We didn't consent to them, and not everyone agrees on them. Some outright reject them, such as D.T. Suzuki and other Zen Buddhist philosophers along with Jacques Derrida and other deconstructionists -- not intellectual lightweights by any stretch. Is there any defense?
As trite as it may sound, these laws of logic are self-evident and really don't need a defense. They are self-evident in the sense that once you understand what the terms mean, it shows itself to be true. The law of identity is a perfect example. The law that "A is A" has the same term on both sides of the equals sign, so to speak. It is simply speaks for itself. As Geisler puts it, "Once one knows what 'triangle' and 'three-sided figure' mean, there is no need to prove that a triangle is a three-sided figure. It is simply seen (by rational intuition) to be true." (Geisler, ST Vol. 1 Ch. 5)
Additionally, any attempt to deny or refute these basic laws destroys itself instantly. No one can deny these laws without using them in the denial, and thereby immediately destroying the basis for the denial in the first place. It is like saying "I think that I cannot think" or "I know that I cannot know" -- you're doing precisely what you claim you cannot do. If the law of noncontradiction is not true, then A can equal not-A; what is true can also be false at the same time. However, the statement "the law of noncontradiction is false" itself claims to be true and not false, and thereby refutes itself. In a sense, no refutation needs to be made of attacks on the laws of thought -- each attack refutes itself. All that needs to be done is exposing that fact.
Still, some (mostly modern) philosophers reject the laws of logic, especially the law of noncontradiction and, to a lesser extent, the law of excluded middle. Jacques Derrida, for instance, dispensed with the principle of noncontradiction, in fact calling his own philosophy "a joyous self-contradiction" which "delights in being without defense." (Derrida, "P" in EU) For Derrida, contradictions are not a problem. Contradictions are inevitable, and we needn't be so caught up in trying to resolve them. Furthermore, Derrida referred to "the empire of reason" and saw logic and reason as not only unfounded and unjustified, but also as merely another set of tools of oppression used by elites. (Derrida, "PR" in EU)
So, my question to you is: what do you think? Should we accept the laws of logic? Does logic apply to reality? What are we to make of those who reject logic? This was a rather hotly debated point in my philosophy class, so I'm anxious to get input. What say you?
Derrida, Jacques. "Punctuations: The Time of a Thesis" and "The Principle of Reason: The University in the Eyes of its Pupils" in The Eyes of the University.
Geisler, Norman and Ronald Brooks. Come, Let Us Reason
Geisler, Norman. Systematic Theology Vol. 1
Suzuki, D.T. An Introduction to Zen Buddhism