CSCE 235 /title>  <style>  </style> </head> <body lang=EN-US style='tab-interval:.5in'> <div class=Section1> <p class=MsoTitle>CSCE 235</p> <p class=MsoTitle><span style='font-size:18.0pt;mso-bidi-font-size:12.0pt'>Light Bulb 1 <o:p></o:p></span></p> <p class=MsoTitle><span style='font-weight:normal'>January 22, 2003<span style="mso-spacerun: yes"> </span><o:p></o:p></span></p> <p class=MsoTitle align=left style='text-align:left'><![if !supportEmptyParas]> <![endif]><o:p></o:p></p> <p class=MsoHeader style='margin-left:.25in;text-indent:-.25in;mso-list:l6 level1 lfo1; tab-stops:.5in'><![if !supportLists]>1.<span style='font:7.0pt "Times New Roman"'> </span><![endif]>Logic is very useful in many areas.<span style="mso-spacerun: yes"> </span>For example, if you are building a circuit board with AND gates, OR gates, multiplexers, and so on, then you need to know how to use logic to plot out your design, to implement the transformation that you want to perform on the input to get the output.<span style="mso-spacerun: yes"> </span>Another example is in Artificial Intelligence (AI).<span style="mso-spacerun: yes"> </span>Suppose you want to build a machine (or a software program) that reasons.<span style="mso-spacerun: yes"> </span>That is, given data or observations, a machine that can think and derive some conclusions for you.<span style="mso-spacerun: yes"> </span>Logic provides for that.<span style="mso-spacerun: yes"> </span>Logic is well-defined.<span style="mso-spacerun: yes"> </span>It has laws that bring one proposition to the next.<span style="mso-spacerun: yes"> </span>It allows reasoning to be specified in valid steps that are consistent and predictable.<span style="mso-spacerun: yes"> </span>In this way, we can build machines that think logically to perform menial tasks or time-consuming thinking tasks for us.<span style="mso-spacerun: yes"> </span>Logic is very useful in AI.</p> <p class=MsoHeader style='margin-left:.25in;tab-stops:.5in'><![if !supportEmptyParas]> <![endif]><o:p></o:p></p> <p class=MsoHeader style='margin-left:.25in;text-indent:-.25in;tab-stops:.5in'>2.<span style='mso-tab-count:1'> </span>When you argue with another person, there are two things that you can attack; or when you are involved in a debate, there are two things that you can focus on:<span style="mso-spacerun: yes"> </span>the hypotheses and the logic.<span style="mso-spacerun: yes"> </span>Sometimes, the hypotheses or assumptions are correct but the logic is incorrect.<span style="mso-spacerun: yes"> </span>For example, suppose the assumption is “If I do not study hard, I will not get an A in the class.”<span style="mso-spacerun: yes"> </span>But if you infer from the assumption the following conclusion, “If I study hard, then I will get an A in the class.”<span style="mso-spacerun: yes"> </span>Then it is logically incorrect.<span style="mso-spacerun: yes"> </span>The assumption does not guarantee an A.<span style="mso-spacerun: yes"> </span>All it guarantees is that if you don’t study hard, you will not get an A in the class.<span style="mso-spacerun: yes"> </span>So, the conclusion may be true in some cases, but it is not logically correct.<span style="mso-spacerun: yes"> </span>So, pay attention to your future arguments and debates.<span style="mso-spacerun: yes"> </span>Pinpoint the assumptions and the logic.<span style="mso-spacerun: yes"> </span>Is the logic sound?<span style="mso-spacerun: yes"> </span>If not, then the arguments should not hold even if the conclusions are correct.<span style="mso-spacerun: yes"> </span>Are the assumptions incorrect even though the logic is sound?<span style="mso-spacerun: yes"> </span>Then, you switch your debate focus to the assumptions.<span style="mso-spacerun: yes"> </span>And so on.<span style="mso-spacerun: yes"> </span>Logic should sharpen your analytic skills.<span style="mso-spacerun: yes"> </span>A conclusion that is false may be false because of incorrect assumptions, or because of bad logic.<span style="mso-spacerun: yes"> </span>Remember that.</p> <p class=MsoHeader style='margin-left:.25in;text-indent:-.25in;tab-stops:.25in'><span style="mso-spacerun: yes"> </span></p> <p class=MsoHeader style='margin-left:.25in;text-indent:-.25in;tab-stops:.25in'>3.<span style='mso-tab-count:1'> </span>One popular branch of AI is expert systems.<span style="mso-spacerun: yes"> </span>Expert systems are software systems that are able to perform tasks for experts, replacing the experts to some degree and thus automating some processes.<span style="mso-spacerun: yes"> </span>Tasks such as classifications and diagnostics are popular.<span style="mso-spacerun: yes"> </span>In a classification task, the goal is to look at the input data, and classify them into some classes.<span style="mso-spacerun: yes"> </span>In a diagnostic task, the goal is to look at the symptoms, and then find out the cause.<span style="mso-spacerun: yes"> </span>In classification, the reasoning is forward.<span style="mso-spacerun: yes"> </span>In diagnosis, the reasoning is backward.<span style="mso-spacerun: yes"> </span>These expert systems usually end up using some sort of a variant of the formal prepositional logic.<span style="mso-spacerun: yes"> </span>In the backward reasoning, for example, the contrapositive law is often not observed.</p> <p class=MsoHeader style='margin-left:.25in;text-indent:-.25in;tab-stops:.25in'><![if !supportEmptyParas]> <![endif]><o:p></o:p></p> <p class=MsoHeader style='margin-left:.25in;text-indent:-.25in;mso-list:l1 level1 lfo8; tab-stops:.5in'><![if !supportLists]>4.<span style='font:7.0pt "Times New Roman"'> </span><![endif]>In the real world, you will encounter many types of logic.<span style="mso-spacerun: yes"> </span>Fuzzy logic, for example.<span style="mso-spacerun: yes"> </span>Do not be intimidated by them.<span style="mso-spacerun: yes"> </span>The fundamental advantage of logic is that it defines a set of structures and a set of permissible, valid “moves” that allows you to traverse from one structure to another.<span style="mso-spacerun: yes"> </span>It’s like a map of cities and the highways connecting the cities, where cities are the structures and the highways are the logical moves.<span style="mso-spacerun: yes"> </span></p> <p class=MsoHeader style='tab-stops:.5in'><![if !supportEmptyParas]> <![endif]><o:p></o:p></p> <p class=MsoHeader style='margin-left:.25in;text-indent:-.25in;tab-stops:.25in'>5.<span style='mso-tab-count:1'> </span>In Star Trek (the movie and the TV series), Spock the Vulcan is a being who thinks logically.<span style="mso-spacerun: yes"> </span>That is, given assumptions, he can derive the proper conclusions without irrational or emotional considerations.<span style="mso-spacerun: yes"> </span>So, in a way, we can say being logical is to be rational and not emotional.<span style="mso-spacerun: yes"> </span>However, we can deal with emotions or irrationality with logic as well!<span style="mso-spacerun: yes"> </span>If we know our decision-making or reasoning process is going to be emotional, then we can model that into our logic!<span style="mso-spacerun: yes"> </span>So, being logical does not necessarily preclude you from considering emotional.<span style="mso-spacerun: yes"> </span>You may still be logical as long as you are aware that you are being emotional!<span style="mso-spacerun: yes"> </span></p> <p class=MsoHeader style='tab-stops:.25in'><![if !supportEmptyParas]> <![endif]><o:p></o:p></p> </div> </body> </html>