Lsat: Logical Reasoning

Front 1

Necessary or sufficient indicator?

Unless

Back 1

Sufficient

Front 2

Necessary or sufficient indicator?

if only

Back 2

Necessary

Front 3

Necessary or sufficient indicator?

Only

Back 3

Necessary

Front 4

Necessary or sufficient indicator?

Whenever

Back 4

Sufficient

Front 5

Necessary or sufficient indicator?

When

Back 5

sufficient

Front 6

Necessary or sufficient indicator?

Where

Back 6

sufficient

Front 7

Necessary or sufficient indicator?

only if

Back 7

necessary

Front 8

Necessary or sufficient indicator?

Always

Back 8

necessary

Front 9

Necessary or sufficient indicator?

must

Back 9

necessary

Front 10

Necessary or sufficient indicator?

requires

Back 10

necessary

Front 11

Necessary or sufficient indicator?

anyone

Back 11

sufficient

Front 12

Necessary or sufficient indicator?

All

Back 12

sufficient

Front 13

Necessary or sufficient indicator?

Every

Back 13

sufficient

Front 14

Necessary or sufficient indicator?

If

Back 14

sufficient

Front 15

Necessary or sufficient indicator?

Only when

Back 15

necessary

Front 16

Necessary or sufficient indicator?

Only where

Back 16

necessary

Front 17

Necessary or sufficient indicator?

Unless

Back 17

* negate one idea, then make it the sufficient

Front 18

Necessary or sufficient indicator?

Until

Back 18

* negate one idea, then make it the sufficient

Front 19

Necessary or sufficient indicator?

Without

Back 19

* negate one idea, then make it the sufficient

Front 20

Necessary or sufficient indicator?

Or- inclusive

Back 20

* negate one idea, then make it the sufficient

Front 21

Necessary or sufficient indicator?

None

Back 21

* negate one idea, then make it the necessary

Front 22

Necessary or sufficient indicator?

Not Both

Back 22

* negate one idea, then make it the necessary

Front 23

Necessary or sufficient indicator?

Never

Back 23

* negate one idea, then make it the necessary

Front 24

Necessary or sufficient indicator?

Cannot

Back 24

* negate one idea, then make it the necessary

Front 25

What are the 3 types of OR? describe each.

Back 25

o Inclusive meaning- “and/or” * most often used.John either enrols in Economics or Poli Sci. § ** the LSAT sees this as he could take one orboth classes

o Exclusive meaning – “or, but not both”- You maysit at one end of the table or the other

§ Used for bi-directional conditions, will oftensay, “but not both”

o Simply “and” – “Jane is a faster eater thaneither Mary or Jon

§ *** here you will see some comparison- fasterthen, harder then, better then etc.

§ * “either” doesn’t necessarily mean exclusivityon the LSAT

Front 26

what should I remember about none, no, both, never, cannot?

Back 26

o BE CAREFUL** The indicator does NOT affect theidea! Having the “none” there does not make Americans /A right away!

Front 27

What two ways can "the only" be used?

Back 27

o The only students who got As were the ones whostudied

o Horses are the only animals that are strong S->H1

- Just remember, what is right after “the only” isthe sufficient

Front 28

How do you form a contrapositive?

Back 28

- “flip and negate” to make a contrapositive! MUSTDO BOTH

- the negation is NOT the opposite. The negationof cold is “not cold” not “hot”

Front 29

What are Most strongly supported questions like?

Back 29

- basically take the conclusion out and hide itinside the answers

- don’t think that these are all like Main pointquestions. some, however, ask a question on a small detail in the passage, thatisn’t the main point, but this answer is most strongly supported by the passagethan the others

- details!

Front 30

What words let us know that what has preceded was context?

Back 30

However, But,and Although

Front 31

What words are premise indicators?

Back 31

For, Since,and Because

Front 32

What is an intermediate conclusion?

Back 32

a phrase which is a conclusion to oneargument and then a premise for another

* be careful, dont let "thus" or "therefore trick you into thinking an intermediate conclusion is the main one

* pay attention to who is talking, make sure the main conclusion alines with their views not others presented in the passage

Front 33

What are the steps for analyzing necessary- sufficient relationships?

Back 33

1) find the indicator

2) identify the two ideas or events

3) Apply translation rule

4) translate back to english

Front 34

the word "both" in sufficient-necessary relationship translation

Back 34

- when there is a “both” like a “not both” “aren’t…Both”“both.. cannot” your two ideas are the two things the both is referring to!

- There arent enough buns for both of the kids to be full

- idea one: K1 being full

- Idea two: K2 being full

K1--> /K2 ot K2--> /K1

Front 35

neither nor in sufficient-necessary translation means...

Back 35

- not one, and not the other

Front 36

Random words that function as necessary...

Back 36

is required, is necessary for, is essential

Happiness is necessary for a good life

GL--> H

Front 37

what do you do when there are both types of "negate and make necessary/sufficient" groups in one sentence?

ex. Never go to Hawaii unless you want to have a good time

Back 37

- You can follow the rules for either words, just make sureyou use the other word as a negation on that idea.

- If you want to use the rule for Unless, then use the“never” as a negation- so symbols= /H and GT then follow rule---negate and use“unless idea” as the sufficient : H-->GT or /GT-->/H

Front 38

How do you weaken or strengthen an argument?

Back 38

you either break down the support premies have for the conclusion using assumptions (weaken), or you block these assumptions by saying they are true (strengthen)

Front 39

Co-incidence vs correlation; How do you debunk each?

Back 39

- A co-incidence is like two specific thingshappening together once. A correlation is like in general, these two thingshappen together

- Co-incidence : just check for competing explanations

- Correlation: check the chronology, check ifthere is a third variable (block it or introduce it), and check

Front 40

What are the 9 valid forms of arguments on the LSAT? MEMORIZE

Back 40

a) A is B, __ is A therefore __ is Bb) A is B. __ is not B therefore ___ is not A

c) A is B. B is C. Thus A is C.

d) A some B. All B C. thus A some C. Some dogs arecute, all cute things are loveable, therefore some dogs are loveable

e) Most A are B. All B are C. Thus most A are C.

f) All A are B; All A are C. therefore Some B are C

g) All A are B. Some A are C. Thus Some B are C.

h) All A are B. Most A are C. Thus Some B are C.

i) Most A are B. Most A are C. Therefore, Some Bare C

Front 41

What does some mean? All? what are they negated?

Back 41

Some= 1-100 range (at least 1); can mean ALL

negation: NONE

ALL= universal quantifier but implies also an existential relationship; It is a point not a range.

All implies most which implies some

negation: Some...Not. Or....And..Not...

Front 42

What does FEW mean? MANY?

Back 42

- many means “some” -

don’t be confused into thinking that may means alot and some means a little

Few

-“some are” but “most aren’t”

- typically they want you to understand that mostaren’t

- few= DsomeE and D-m-> /E

Front 43

What does most mean?

Back 43

- ranges from 51-100

- like some, this can also mean ALL!

- Most is a subset of Some

Front 44

What are the 7 invalid argument forms? MEMORIZE

Back 44

a) A--> B therefore B-->A

b) A-->B/A therefore /B

c) A-->B;B some C. Therefore A some C (here, this COULD be true, but inferences MUST betrue)

d) A-->B;BmostC. Therefore Amost C

e) A some B some C. Therefore A some C

f) A most B most C. Therefore A- Most- C

g) A some B. A some C. therefore B some C

Front 45

And // Or in sufficient conditions

Back 45

-when 'or' is in the sufficient, the two elementsare independently sufficient

- so EorG-->P means E-->P and G-->P

'And' means the two elements are jointly sufficient, so they do not split.

If E and G then P means EandG-->P

Front 46

And// or in necessary conditions

Back 46

- opposite of the sufficient ones

- 'and' elements split

if E then Aand B means E-->A and E-->B

'Or' elements do not split

- if E then A or B means E--> AorB

Front 47

And/or in contrapositives (DeMorgans Law)

Back 47

you flip around like you normally would, but 'and' becomes 'or' and 'or' becomes 'and' and then you negate everything like normal

Front 48

Biconditionals: Either or, but not both

Back 48

-Allan or Chris goes to the park, but not both.

- remember that "but" means "and"

- So Thiscan be broken down into “Allan or chris goes to park = /A-->C or /C-->A” and “Allan and Chriscannot both go to the park= A-->/Cor C--> /A” so what you get is /A<-->C or A<-->/C

* contrapositives for bidirectionals just mean switching the "not" because they are both the sufficient and necessary conditions

Front 49

Biconditionals: If but/and only if

Back 49

- If and/but only if: Allan attends the meeting ifand only if (but only if) Chris attends the meeting

- A<-->C because it is a comboof

“if chris attends” C-->Aand “If Allan Attends” A-->C

- normally we would not know that if A-->B B-->A but with this since it is ONLY IF, then we can make it bidirectional, they are both sufficient and necessary

Front 50

Biconditionals: ...but not otherwise

Back 50

-Allan goes to the park if Chris goes to the parkbut not otherwise.

- Means “ If Chris goesto the park then Allan goes to the park” and “If Chris doesn’t go to the parkthen Allan doesn’t go to the park”

-so C-->Aor /A-->/C plus /C-->/Aor A-->C

- gives us A<-->C

- means the same thing as if and only if

Front 51

Biconditionals: Except

Back 51

- someone on the discussion said that Except = “if and only if” with one term negated

-Allan goes to the park everyday, except whenChris goes.

- Means A-->/C plus /C-->A

-which gives us A<-->/C and /A<-->C

Front 52

What are the two families of bidirectionals?

Back 52

o Always together, never apart: A<-->B and /A<-->/B (like if and only if and not otherwise)

Always apart, never together /A<-->B ( or A<-->/B same thing obvs) (like except and either or but not both)