Skepticism is the philosophical position that doubts that knowledge can be attained absolutely, yet it affirms that things cannot be known. However, to what degree of certainty such knowledge can be had is debated. Skepticism could be said to be a search for knowledge, but that all knowledge must remain under scrutiny; hence, skepticism. Scientific skepticism says that though science is extremely valuable in gaining knowledge, it has also taught us that what we believe to be true is very often found to be false. Therefore, scientific skepticism leaves knowledge gained through the scientific method open to being challenged.
The problems with skepticism are many. How does a person begin to acquire knowledge without being skeptical of the very means by which that knowledge is attained? Furthermore, we must presuppose the validity of the laws of logic in order to rationally examine everything, including her own skepticism. But are the skeptics skeptical of the laws of logic or do they presuppose their validity? Two presuppose their validity is to violate one's own skepticism. Then again, some skeptics grant that we must have a place to begin in our discussion and examination of truth values. So, they conclude that an infinite regression of skepticism where were skeptical about our beginnings of a search for knowledge is untenable.
Of course, skepticism does not necessitate that everything is doubted all the time. Otherwise, progress in the various categories of study (philosophy, mathematics, engineering, medicine, etc.) could not be made. Nevertheless, the value of skepticism is that once undertaken, it can lead to greater understanding and knowledge. So, skepticism is a philosophical approach to learning that must presuppose the validity of laws of logic in order to function.
But, everyone has presuppositions even if they presuppose the validity of skepticism. So, ultimately, skepticism has a place of value but it must assume certain values such as laws of logic, the uniformity of nature, etc. The question then becomes, which worldview best accounts for those presuppositions?