{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

LPL 2.1 lecture - Can you think of a case that would...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Valid & Sound Arguments What is an argument? one or more premises conclusion conclusion is said to follow from or be supported by the premises Consider the following argument: All men are mortal. Socrates is a man. So, Socrates is mortal The argument intends to show that Socrates is mortal, so the last sentence is the conclusion. The other two sentences provide support for the claim that Socrates is mortal, so they are the argument’s premises. Two types of arguments: Logically valid – If all the argument’s premises are true, then the conclusion must be true as well. Logically invalid – Even if all the argument’s premises are true, the conclusion my still be false. Compare the following arguments: (1) All men are mortal. Socrates is a man. So, Socrates is mortal (2) All men are mortal. Socrates is mortal. So, Socrates is a man. The first argument is valid because its conclusion necessarily follows from its premises. The second argument, on the other hand, is invalid because its conclusion does not necessarily follow from its premises.
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Can you think of a case that would demonstrate that the second argument is invalid? Sound and Unsound arguments: An argument is said to be sound if it is valid and all of its premises are true . Consider the following arguments: (1) All men are mortal. Socrates is a man. So, Socrates is mortal. (2) All rich actors are good actors. Brad Pitt is a rich actor. So, Brad Pitt must be a good actor. What about this one: (3) All rich actors are good actors. Brad Pitt is a good actor. So, Brad Pitt is a rich actor. Regardless of the truth value of the premises and conclusion, all invalid arguments are automatically unsound . A note about Fitch format for arguments… All men are mortal. Socrates is a man. So, Socrates is mortal. When we begin to analyze arguments we will use the Fitch format to display each argument. In Fitch format, the premises are listed before the horizontal line (called the Fitch bar) and the conclusion is listed below the line....
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern