Introductory Logic: Basic Reasoning

I had a little bit of discussion with one of my new housemates the other night, and though he jumped through many things, one part was directly related to bad reasoning and bad defence of arguments.

First, he made the claim that we are decedents from an alien race that came to earth right before ancient Egypt was formed, and they mixed their DNA with apes to make us, human beings. When I asked what is his reason for this claim, he said that one particular theory about how Egyptians made the pyramid has been falsified, and since no scientist can explain how the pyramid were made, this is evidence for the alien race.

Of course now you think that I should have left it at that, since these claims are beyond repair messed up. But, well, not me. I at least try my best, so I told him that I do not know much about pyramids, but what he is doing is appealing to ignorance: He is backing up his claims not by providing evidence for them, but by saying that since other people are wrong, his explanation must be right.

At this point he did something that is the subject of this post, he asked: “Do you doubt that aliens might exist?”

The answer to that question as physicists have suggested is most likely no, aliens are highly likely to actually exist, but that doesn’t mean that they have ever visited us, or even to have survived long enough to realized that we exist.*

This is when I felt the need to explained something essential about reasoning: Conclusions (or different parts of them) may or may not be obvious, but no one can defend a fallacious argument based on partially obvious conclusions.

Take the following argument for example:

All insects have eight legs.
Spiders are insects.
==> Spiders have eight legs.

The conclusion is obviously true, but the argument is utterly false. If someone present such argument, and then when told that the argument is false defends it by saying “If you do not believe me, let’s go and see a spider for ourselves!”, they are abandoning the basics of reasoning.


* The following video is a good speech from Richard Dawkins in which he talks about this issue as well as science and fallacious arguments. (This particular issue comes up around 35:30)


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Dear fellow Homo sapiens, or if you prefer conscious mammals! And of course, friends nonetheless: I created my blog in order to speak my very weird mind, mostly about three subjects (as I identify myself and my state of mind with them): Atheism, as I was born in the Middle East and saw and felt the affects of Islam; Homosexuality and equal rights, as a gay man who has tasted the Homophobia and also Sexism in that society; and Liberalism and political philosophy, which I think is a good ground for secular values and criticism of fundamentalism. If you wish, visit and join your state of mind to mine. I hope they don't short circuit!

5 thoughts on “Introductory Logic: Basic Reasoning”

  1. I have a question: Who is the bigger Fool -The Fool or the Person who tries to reason with a Fool.

    I understand your desire to try to understand his reasoning and logic behind why we are all descendants of an ancient alien race, but even though every may be possible, not everything is reasonable.

    1. Thank you for the comment.

      Well I don’t have the desire to understand his reasoning, not exactly since that part is actually quite easy. What I have is probably the desire to try and change his his mind by reasoning with him and showing where he is wrong. Of course he makes more and more fallacies (to the point of ad hominem, by calling me dogmatic, or narrow minded or comparing me with children who think they are always right).

      But still I do not care. Again I point out these fallacies. Untill he finally changes the subject. In the meantime, if he is interested in what is true or not, HE will go after logic to try and challenge me my own way. This is what I wish to happen.

      Of course, most of the times this does not happen. I’ve had many discassions with many people, and I don’t think they immediately changed their minds or went after logic text books. I just hope that I have been able to put the seed there, the curiosity.

      1. I understand your desire to make the other person see your logic or just simply have a better understanding of logic. But the simple fact is…..Not everybody is a rational logic being.

        I work in sales, and this is the one thing I have learned to use to my advantage. i.e. The act of purchasing a product/service is not a rational/logical choice. They are not doing it cause it makes rational or logical sense. Not because the purchaser as evaluated all available options to make the most rational/logical choice. The are making the decision out of emotion. Because it feels good. They are buying because the purchasing experiences or product/service makes them feel good about themselves

  2. Certainly I did not suggest everybody is rational. What I say is that I hope they are capable of being rational. And of course that is not to say everybody is capable of being rational, many may not be, or even not want to be; but yet, we wouldn’t know if we do not try now, would we?

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