Skepticism from an astrological symbolism perspective: The symbols I most associate with skepticism are Mercury and Saturn. Mercury symbolizes and relates to, in general, the intellectual, left brain, linear logical side of us. Our conscious minds.
I've noticed that people with very powerful Mercury in their charts, tend to have a good amount of some kind of yellow and/or tan color. If it's linked to a very strong Sun at the same time, usually it's more towards the rare, "golden yellow" shades, which are faster vibratory and more infused with White Light that relates to PUL.
Mercury, all in all, relates to the more positive side of skepticism, which is the necessary grounding balance of the left brain, logic type pattern, on the receptive/receiving right brain.
Saturn and skepticism: Saturn relates more to the fear based aspect or level of skepticism. Mercury desires clarity and truth for the sake of same. These are inherently important to Mercury.
Saturn on the other hand, is very "socially conscious". Saturn is very related to not only fear in general, but especially one's self image in relation to "what will others think" ego type fear/worry.
Let's use a more concrete example. Say you were born with Mercury in Capricorn, closely opposed Saturn in Cancer. Mercury in Capricorn, is already careful, methodical, cautious, deliberate, and fairly grounded. Cancer is a Sign that tends strongly towards self protection and defensiveness, especially emotionally.
Saturn in Cancer, would only highlight that pattern. But what happens when you take Capricorn Mercury + Cancer Saturn in a powerful, direct aspects, it = a mind that has a strong pattern and tendency to be VERY worried and concerned about being accurate and correct in general, and especially in relation to one's socially oriented self image. A very strong concern and attachment to being perceived as accurate or well thought of in the mental sense.
If a more mature Soul is born with such a pattern/indication, they probably will channel it mostly constructively, and the Love they attune to and become aware of, can help over-ride some of the less positive, possible expressions. But, chances are, they will very strongly tend towards the a mental approach of skepticism, and at times, probably too much so.
Here is a link talking a little more about Saturn in a more holistic way:
http://afterlife-knowledge.com/cgi-bin/yabb/YaBB.cgi?num=1495135766
As I basically said earlier, I think faith needs to be balanced with skepticism and skepticism balanced out with faith. Faith is more innate Love attuned and not concerned with self image, and is ready to dive in where Angels fear to tread. Faith is standing up on a cliff, looking down into the water, jumping off knowing you will be ok. Where there is a lack of self focus and consciousness, there tends to be positive faith tendencies and expression.
This is the faith aspect that Yeshua focused on, and for a reason. He knew that his Piscean Age, would morph into a very intellectually polarized time period/cycle, and his messages about faith, were not just for the people around or his times, but for also for this future time of intellectual polarization.
Astrologically, the concept of faith relates most to the Planet Jupiter. A good counter balance to over Mercury Saturn attunement, especially if it become non constructive, is that of Jupiter. For example, take that same Mercury in Capricorn position and instead of combining with a powerful aspect to Saturn in Cancer, you combine with a very close trine to Jupiter in Virgo.
This would indicate a much more balanced and positively faith informed kind of mind set and approach. You have the natural skepticism, depth, penetration, and groundedness of Capricorn, but combined with the very expanded, positive, very intuitive, more Love/Universal Consciousness that Jupiter represents.
Jupiter's "dark side" is that of "over doing", usually of that which is positive otherwise. Capricorn Mercury here, would lend a necessary balance to faith filled Jupiter, and vice versa Jupiter would balance out the limiting tendencies of Capricorn Mercury.
I tend to like to look at conditions and patterns very holistically. Astrology might be a new language to some here, and not familiar, but it can really help one to become more conscious to that which tends to be unconscious in life, others, and/or self. Besides going within and contacting positive Guidance and meditation in general, I would say astrology is one of the most potent ways to be able to peer into the unconscious and/or shadow side of self and/or others.
I did full charts from age 16 to 26 or so for others. It has always amazed me, and though it's not much of a focus anymore, it's still interesting to look at things from this "multi-leveled consciousness symbolism language". It powerfully reminds me constantly, of how One everything truly is.
Astrology is like a combo of microscope and telescope into the larger Universe of Consciousness. Course, like anything language related, your ability to perceive and interpret matters a lot in it's degree of helpfulness.