Explain what logic can and cannot do?

http://www.google.com/search?hl=en&q=what+logic+can+and+cannot+do&oq=what+logic+can&aq=1&aqi=g2&aql=1&gs_l=serp.3.1.0l2.47238l49808l0l54819l14l14l0l1l1l0l145l1430l0j11l11l0.pfwc.1.

Let us know what you think.