Those that are intelligent know what they do not know. Many people feel that acknowledging a mistake makes them stupid. Smart people acknowledge mistakes and do not repeat them. On the flip side of this, I personally will take advise and consider it to possibly be fact only after I have proved it myself and or have gotten the same facts from three different sources. I never repeat advise without testing it myself. I find that most people do not think in these terms. If they did there would not be a shortage of engineers.