conditional reasoning question

[voodoochild]

I have a quick question : when I say that: If I work for long hours for my exam, I will run a significant risk of mental blockage.

Does it mean that "working long hours for my exam" is the only way that I run a significant risk of mental blockage? I am a bit confused.

Can you please help me?

Thanks

[Steve Stein]

Hi Voodoochild,

Just think about this in the real world.

If I say that drinking a dozen sodas will make me sick (dozen sodas sick),

am I saying that is the only way I can possibly get sick? no.

All I know is this:

If I drink a dozen sodas, I will get sick.

And if I do not get sick, I have not drunk a dozen sodas.


I hope that's helpful!

~Steve

[osubucknut26]

I'm confused. If drinking the dozen sodas makes you sick, wouldn't the sodas be the necessary condition, and wouldn't it be diagrammed sick ----> sodas ? I'm having a very hard time with setting up conditional reasoning diagrams.

[Steve Stein]

Hi,

Thanks for your question. If you drink 12 sodas, you'll get sick. What does that mean? Not that you absolutely need those 12 sodas to get sick--you could also catch a cold, for example.

What that actually means is that those 12 sodas are enough to get you sick--drinking those 12 sodas is sufficient to make you sick. 12 sodas sick

I hope that's helpful! Please let me know whether it's clear--thanks!

~Steve

[Dave Killoran]

Hey OSU,

Let me add a point to Steve's answer. Think about a few of the things that could make you sick:

drink 12 sodas
germs
staying outside in cold weather too long
etc

If you diagram the relationship as sick drink 12 sodas, then what you are saying is that every time you are sick, you drank 12 sodas. That doesn't really make sense, so it's the other way around: drink 12 sodas sick.

So, if you were debating between which term was sufficient and which term was necessary, you'd say, "Which one always forces the other to happen?"

• If I'm sick does that mean I drank 12 sodas? No, so sick isn't the sufficient.
  
  If I drank 12 sodas, does that mean I'm sick? According to the author, yes, and so 12 sodas is sufficient.

I hope that helps. Thanks!

[osubucknut26]

Thanks for the help. This problem is much clearer for me but I am still making mistakes in the book. Would you be able to give a couple more examples and walk through the thought process of identifying the sufficient and necessary conditions for each situation? That would be extremely helpful and I think I would finally catch on. Sorry I'm just really having a tough time with the concept.

[Dave Killoran]

Sure! I'll toss a few examples in, but knowing what you are missing would be a big help.

90% of the time, it's all about the indicators. Whenever you see words like "if," "all," "only" and so forth--the words on our indicator lists--just follow those and turn into a diagramming machine. Examples:

• 1. Every student in this school wears a uniform.
  
  2. Trilobites are found only in rock strata from prior to the Permian era.
  
  3. I go to the store when I have money.

The same statements, with diagrams, and conditional indicators italicized:

• 1. Every student in this school wears a uniform.
  
  Student in this school wear uniform
  
  2. Trilobites are only found in rock strata from prior to the Permian era.
  
  Trilobite found in rock strata from prior to the Permian era
  
  3. I go to the store when I have money.
  
  I have money I go to the store
  
  Note how nonsensical this third one is...but that's what the author actually said, so that's the diagram

Let's start there, and if you can point me to a few problems you mis-diagrammed, I will then know where to go next.

Thanks!

[josuecarolina]

Also, if I can humbly submit; sometimes the terms 'sufficient' and 'necessary' confuse us, especially at the beginning. I often found myself thinking that if something is necessary, it's more important than being sufficient so it should come first. I don't know why, maybe because when we diagram importance/best/first in games it's always to the left.

Anyway, Thinking of a chicken and Egg helps me. Sufficient is always the chicken, necessary is always the egg.
A chicken (hen) is sufficient to have an egg. Other things could have eggs too...say snakes, but 'it suffices' to say', a hen will get you an egg. (another term for sufficient could be 'adequate')

An egg is NECESSARY to get a chicken. No egg, for sure no chicken (or anything else that comes from an egg:))

I don't know if that helps at all, but it helped me a lot at the beginning (I started last July, taking it in 2 weeks

[Dave Killoran]

That's a great way of thinking about it--nice work!

A lot of time, I think of the sufficient as a signal--it signals/tells you/indicates that something else has to happen. The necessary doesn't do that. It's essential, but it just sits there and by itself doesn't signal anything to you.

Thanks!