Direction of Arrow in Making Inferences

[ban2110]

Hallo,

I'm a little confused about something regarding the direction of arrows in making most out of some inferences.

A some C
A ---> B
---------------
C some B

This inference I can arrive at with no problems. The problem occurs when I try to go a step further. Since "most" inferences are unidirectional, I am confused as to which direction I should go to make the inference.

C most B or B most C?
Or are both valid inferences?

Thank you so much for all the help!

[chike_eze]

If I understand your question correctly, then MOST is unidirectional, only SOME is bi-directional.

A --most--> C

means, most of A is C, however, this does not necessarily mean that most of C is A. Why? because C could be a much bigger set than A. (Venn diagrams are helpful to see this)

i.e., A--most--> C is not equivalent to C--most-->A

A some C, on the other hand, is equivalent to C some A.

[chike_eze]

A --most--> C
-------------
A some C
C some A

A --> C
------------
A --most--> C
A some C
C some A

[ban2110]

Thank you so much for replying!

Though I am still confused, thanks to your post I am now better able to explain my confusion!

What if you're not given the "all" statement and instead given only the "some" statement. How would you go about making a "most" inference from just that?

For instance, you're only told: A <--> C. Is it possible to make a most inference given just that piece of information? If so, how would you know it's A most C instead of C most A?

Thank you again for all your help!

[ManhattanPrepLSAT1]

Hi ban2110,

Glad to be of help here. Remember that A <--> C means that "all A's are C's" and also that "all C's are A's."

So to your question about whether you would know A -most-> C or C -most-> A, actually, you would know both!

Here's a table that you could use for working on finding inferences when working with quantified statements.

[ban2110]

Hi ban2110,

Glad to be of help here. Remember that A <--> C means that "all A's are C's" and also that "all C's are A's."

So to your question about whether you would know A -most-> C or C -most-> A, actually, you would know both!

Here's a table that you could use for working on finding inferences when working with quantified statements.

Thanks so much for this chart! It's been an immense help during my review!