One of the biggest problems that Derrida raised and tried to answer during his lifetime was the intersection between our ability to communicate, meaning our language, and the internal realities that we are trying to communicate.
You have to understand that Plato was saying that there is such a thing as ideal forms. These things are real, regardless of how we express them and regardless of their manifestations in our present everyday experience.
For example, the idea of a cat is going to remain pure and unchangeable regardless of the fact that most of the cats you see in your everyday waking experience are spotted or speckled. You still know that they are cats because you have the idea of a cat planted in your mind.
The idea, in and of itself, has some sort of self-defining and self-fulfilling power. So regardless of where you are put on this planet, since you have the idea of the form of a cat and what constitutes a cat, you can easily spot a cat and, with certainty, say that you are looking at a cat regardless of whether you’re in China, the Philippines, Lithuania, Ukraine, Ecuador, Mexico or California. Sounds awesome, right?
Well, the problem here is that it relies on the logic created by the power of symbolism. In other words, the logic is only as good as your ability to communicate it through the symbols.
Derrida destroyed the symbolism, or at the very least called into question. This is why philosophers now are saying, “Is there a better method? Is there a better way to arrive at the truth without having to cross that cross street between symbolism and logic?”
That is the pickle that Derrida has put us in. And it’s still too close to tell whether any successor bodies of philosophy have successfully answered this question because it is very profound. And it’s very heavy because if you were able to knock the support out of this intersection, you pretty much are in a situation where there is no truth.
It’s anybody’s guess what absolute truth is. And if you were looking for a practical application of this philosophical conundrum, you only need to look at the concept of murder.
It would be comforting to think that murder, in all cultures and in all times, is a bad thing. It would be nice to assume that we could agree that it is true that murder is, was and will always be a bad thing. But unfortunately, Derrida has changed this. And he has asked certain questions that, if taken to their logical conclusion, would make you doubt the concept of murder.
This is why his critics hate him because morality is essentially non-existent in a post-Derrida world. It is no surprise that postmodernism, which is often equated or associated with Derrida is the favorite philosophical whipping boy of the conservative end of the academe as well as social institutions like churches.