The function represented by the Sun in Astrology is that of identity; of the most fundamental element of our personalities; and that which we need to live. The Moon is the function of our personalities that serves to protect our identity; our life; and our existence. The Moon functions in different ways with different energies; so let's look at these different styles. It’s important to remember that the skills and energies of the Moon are not a constant part of our identity, but are energies that we have in certain situations. Reading the following (necessarily incomplete) definitions may not seem to apply, but consider how we react to uncomfortable situations.
Fire Sign Moon
I protect with the passions! Aries Moon protects with aggression, the force of will and action; Leo Moon protects with strength of character and ego; Sagittarius Moon protects with exaggeration and benevolence.
Earth Sign Moon
I protect with values. Taurus Moon protects with what is important to living, such as maintaining the home, belongings or the self; Virgo Moon protects by keeping an analytical barrier, that often comes across as criticism; Capricorn Moon protects with going beneath the presented problem and identifying the salient issues.
Air Sign Moon
I protect with concepts. Gemini Moon protects with words and words and often more words on top of that; Libra Moon will question why cooperation has been sacrificed or lost, and will be waiting for an answer; Aquarius Moon will only feel any need to protect on principle, and when any principle is crossed, there is much vehemence and vindication.
Water Sign Moon
I protect with emotions. Cancer Moon protects with the force of emotional strength and sometimes with guilt; Scorpio Moon protects by going on the offensive, and finding the soft emotional point in the opponent; Pisces Moon protects by voiding emotional contact points, or by spiritualising them.
The Moon also represents our emotional needs, how we make intimate contact with others and the needs we express then, and our perception of our mothers. This last point is interesting, as it intimates our perception of our mothers is also our own defence structure. Fundamentally, this statement stipulates that our perceptions of reality are reality for each person. The Moon rules the Fourth House, and this house represents the stage of childhood where we begin to imprint our emotional natures from the adults around us.
Our deepest psychological level, it can take years and much assistance to uncover and identify exactly what we imprinted when we later become adults, but well worth the effort. Whenever there is a transit to the natal Moon, keep a diary of new decisions made to raise awareness of what the emotional needs there are. It may be embarrassing to admit the erratic or childish impulses that are addressed, but the courage needed to admit can provide a firm foundation for self-confidence.