In today's pop culture, there is one very popular view of the future. All humans will be free to do as they wish, because robots and computers will work for us. Computers are viewed as the ideal slaves. They work non-stop, never complain, and above all, never make mistakes. It is often said that computers don't make mistakes, that it is the person using the computer who commits errors. What is it that makes humans err, but not computers? I will prove that it is simply the way humans are built that makes us commit errors. Unlike computers, built of mechanical or electronic parts, humans are made of organic matter and nerve pathways. These same pathways, with the help of the brain are responsible for all the decision making. I shall demonstrate why humans err, despite the fact that we have eyes and ears to sense with.
	Before I can establish causes for error, I shall define the terms "error" and "mistake". In the context of this essay, they will simply mean that a human obtained a result different from the expected, correct one. Whether it in be adding two numbers, or calling someone by the wrong name, these are all errors that a computer would not make. An error can also be interpreted as being a wrong physical move. If a person is walking in the woods and trips on a branch, it is because the person erred in the sense of watching the path followed.
	There is no doubt in anyone's mind that humans make mistakes all the time. Let us simply analyze any process in which there is a chance for someone to commit an error. Take for example a cashier in a grocery store. The cashier obtains the total on the cash register, and receives a twenty dollar bill from the customer. She must now give the patron back his/her change. The cash register tells the cashier that the client is owed 4.60$. The cashier then reaches into her change drawer to retrieve the proper set of coins. This is where the opportunity for error increases. What if the cashier only gives the customer back 4.55$, because she mistakenly returned a nickel instead of a dime? What caused this blunder? Would this blunder have happened if the cashier had had 15 minutes to decide on how much change to return instead of 15 seconds? Logically speaking, we can establish that if the cashier had 15 minutes to select the proper set of coins, she probably wouldn't have made a mistake. This is due to the fact that she would have taken more time in figuring out which coins to choose and would even have had time to review her decision several times.
	What can we deduce from this discussion? Humans are more prone to make mistakes if they are rushed than if they have lots of time to do an operation. There are many other examples. If you give a class a math exam, but restrict them to 15 minutes, we can be almost certain that they will get a lower mark than the same class doing the same test in one hour. The reason is fairly simple. Our brains and senses simply do not react fast enough. That is why computers are so renown for their dependability in terms of errors. Computers can perform thousands more operations per second than a human with no chance of error. This is due to the construction of these machines. Their inanimate parts are better adapted to executing these operations at very high speeds.
	Let us take another example. A man is adding up a column of numbers. We will pretend that this individual has a basic knowledge of math. The mistakes he might make, if any, will not be due to his lack of knowledge of  the basic addition rules. He sits down with a sheet of paper with a list of many three digit numbers. What kinds of errors can he commit, and why? While adding up the numbers, he might mistake a 7 for a 1 and add the numbers together wrong. He might, while adding, disregard a number once in a while. All these possible mistakes would lead to the wrong final answer, but what causes these errors? Once again, the time factor is very important. Given the chance to redo his calculations another 99 times, he would certainly produce the correct final answer. The reason he committed errors was simply that he was doing an action faster that his brain and eyes could handle with 100% accuracy. It seems that our brains can compute complex operations that allow us to drive a car through terrible weather conditions, at night, but all these operations cannot be accomplished within too short a time limit.
	So far, we have discussed the speed at which the brain can compute operations without error. We must consider other factors which can also lead to mistakes. To explain other types of error, I will use a terminology developed and used by the philosopher Bertrand Russell. He identifies something called sense data. Sense data is the data received by our senses from the object being "sensed". For instance, if a person is looking at a red apple, the shape and color and all other aspects of this apple are received in the form of sense data. In the case of the man adding up the numbers, he mistook a 7 for a 1. What really happened is that his senses misidentified the number. The sense data was received by his eyes, which then converted this information into an electrical signal to be sent to the brain for analysis. There are thus two possibilities. Either the eyes did not transform the signal of the 7 properly, or the brain misunderstood the signal received from the eyes. In both cases, the sense data was analyzed incorrectly, leading to an error in the final calculation.
	Some skeptics might criticize my position by saying that, no matter how much time a person has to complete a job, he or she might still commit errors. In the example of the cashier that I used earlier, one might say that although she had 15 minutes to select 3 different coins, that she still might make a mistake. One could justify this position by saying that this is due to a lack of attention. If a person has 15 minutes to complete a simple task, they will pay very little attention to the details. If the coin is slightly worn out, and the cashier is not paying attention, then she will pick it up by mistake. Moreover, once the coin is selected, she will assume that it is the right one, so that even if she checks the coins before handing them to the customer, she might simply assume that she has selected the correct amount. My answer to this position is fairly clear. No matter how little attention she pays to the job she is doing, that is not where the error lies. If she is distracted while picking up the coins in question, then her senses are not receiving and analyzing the sense datum properly, or thoroughly. This is simply a more complex case of what I described earlier, with the man mistaking a 7 for a 1. The individual is not drawing the right conclusion from the sense data received.
	In light of the examples and discussions presented, I think is safe to say that human error is due to the fact that the brain can only function perfectly up to a certain speed. Also, the five human senses do not always properly interpret the sense data received, causing the brain to make mistakes. Not paying attention to what one is doing is not a reason for making a mistake. It is the repercussions of this behavior that cause the error, because the person is not using his/her senses properly. In conclusion, it is understandable that humans make mistakes despite the fact that our senses receive sense data from objects surrounding us. After all, if this weren't true, you would have just finished reading a perfect essay!