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- Intro to logic
- Introduction
- Defining a proof
You'll lose weight if and only if you burn more
calories than you take in.All those diet-plan books can never get around this,
and all their details are pointless.
True, calorie intake and expenditure solely determine weight loss/gain.
But after some thought, we can get examples where the above logicoverlooks some relevant differences:
If your friend told you they were switching from a diet of2000 calories of balanced short-term and long-term energy sources
(sugars, proteins, and carbs) to a diet of2000 calories worth of Pixy Stix at breakfast
plus a Flintstones multivitamin,would you be optimistic that they would have the willpower
to strictly follow the new plan?The two plans are equal when counting calories, but in actuality
one really is a better plan.(Even more exaggeratedly, consider a daily plan of
2000 calories of sugar while never drinking any watersince
water has no calories, it can't affect your calorie count,according to the above claim.)
These contrived counterexamples help illustrate that
it's conceivable that there
can be a difference
between diet plans, so the initial claim isn't technically true.
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The point illustrated
is that often real-world arguments incorrectlyimply that their result follows from the
form of the argument, when in fact
the form is not valid in the way a syllogism is.This fallacy can be illuminated by finding
a different domain in which the argument fails.The practice of searching for domains which invalidate
the argument can help both sides of a debate hone inon bringing the unspoken assumptions to light.
The original argument, if its conclusion is indeed true,must be patched either by adding the unspoken assumptions
or fixing the invalid form.
Mistakes in syllogisms are hard to make:
what are the only two ways to have an error in a syllogism?
- The argument isn't actually in syllogism form.
For example, the following is an
incorrect syllogism:
| 1 |
All people don't know my file's password. |
Premise
(Equivalent toNobody knows my file's password, but reworded
to be of the required formAll somethings have some property..) |
| 2 |
All hackers are people. |
Premise |
| 3 |
Therefore, my file is secure from hackers. |
Incorrect syllogism, lines 1,2 |
To be a syllogism, the conclusion would have to beall hackers don't know my file's password.The file might or might not be secure, but the above doesn't prove it.
- One of the two premises is wrong.
| 1 |
All people don't know my file's password. |
Premise,
but possibly false |
| 2 |
All hackers are people. |
Premise,
but possibly false |
| 3 |
Therefore, all hackers don't know my file's password. |
Syllogism, lines 1,2 |
This proof fails, of course, if some hackers are
non-people (
e.g. , programs),
or if some people know the password.(In fact, presumably
you know the password!)
Of course, even if a proof fails,
the conclusion might be true for other reasons.An incorrect argument doesn't prove the conclusion's opposite!
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Other inference rules
Of course, there are more ways to deduce things, beyond a syllogism.
- Who decides what the valid inference rules are?
- Is it always clear when people have used the inference rules correctly?
Questions & Answers
what does the ideal gas law states
Three charges q_{1}=+3\mu C, q_{2}=+6\mu C and q_{3}=+8\mu C are located at (2,0)m (0,0)m and (0,3) coordinates respectively. Find the magnitude and direction acted upon q_{2} by the two other charges.Draw the correct graphical illustration of the problem above showing the direction of all forces.
To solve this problem, we need to first find the net force acting on charge q_{2}. The magnitude of the force exerted by q_{1} on q_{2} is given by F=\frac{kq_{1}q_{2}}{r^{2}} where k is the Coulomb constant, q_{1} and q_{2} are the charges of the particles, and r is the distance between them.
Muhammed
What is the direction and net electric force on q_{1}= 5µC located at (0,4)r due to charges q_{2}=7mu located at (0,0)m and q_{3}=3\mu C located at (4,0)m?
what is the change in momentum of a body?
Capacitor is a separation of opposite charges using an insulator of very small dimension between them. Capacitor is used for allowing an AC (alternating current) to pass while a DC (direct current) is blocked.
Gautam
A motor travelling at 72km/m on sighting a stop sign applying the breaks such that under constant deaccelerate in the meters of 50 metres what is the magnitude of the accelerate
What is Thermodynamics
Muordit
velocity can be 72 km/h in question. 72 km/h=20 m/s, v^2=2.a.x , 20^2=2.a.50, a=4 m/s^2.
Mehmet
A boat travels due east at a speed of 40meter per seconds across a river flowing due south at 30meter per seconds. what is the resultant speed of the boat
50 m/s due south east
Someone
which has a higher temperature, 1cup of boiling water or 1teapot of boiling water which can transfer more heat 1cup of boiling water or 1 teapot of boiling water explain your . answer
I believe temperature being an intensive property does not change for any amount of boiling water whereas heat being an extensive property changes with amount/size of the system.
Someone
temperature for any amount of water to boil at ntp is 100⁰C (it is a state function and and intensive property) and it depends both will give same amount of heat because the surface available for heat transfer is greater in case of the kettle as well as the heat stored in it but if you talk.....
Someone
about the amount of heat stored in the system then in that case since the mass of water in the kettle is greater so more energy is required to raise the temperature b/c more molecules of water are present in the kettle
Someone
physics, biology and chemistry
this is my Field
ALIYU
field is a region of space under the influence of some physical properties
Collete
what is ogarnic chemistry
determine the slope giving that 3y+ 2x-14=0
WISDOM
Another formula for Acceleration
pratica A on solution of hydro chloric acid,B is a solution containing 0.5000 mole ofsodium chlorid per dm³,put A in the burret and titrate 20.00 or 25.00cm³ portion of B using melting orange as the indicator. record the deside of your burret tabulate the burret reading and calculate the average volume of acid used?
how do lnternal energy measures
Esrael
Two bodies attract each other electrically. Do they both have to be charged? Answer the same question if the bodies repel one another.
No. According to Isac Newtons law. this two bodies maybe you and the wall beside you.
Attracting depends on the mass och each body and distance between them.
Dlovan
Are you really asking if two bodies have to be charged to be influenced by Coulombs Law?
Robert
like charges repel while unlike charges atttact
Raymond
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Source:
OpenStax, Intro to logic. OpenStax CNX. Jan 29, 2008 Download for free at http://cnx.org/content/col10154/1.20
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