The fetal position represents the state the per-born child exists in unconsciously. For an adult, a physical fetal position is rarely (if ever) taken. What can happen though is a mental state of vulnerability that is proportionately similar to a young child. It is here that a person (young or old) is vulnerable. It is in this state that a person is willing to accept contingencies to normal functionality. This can be either good or bad.
A typical state of a person’s life has them protected by a shield developed either internally or externally. Those who rely on an external shield appear quite feeble and vulnerable. But, where an internal shield is lacking, an external shield is relied upon.
Everyone, at one point or another, puts down their internal shield, or puts any trust in any external shield(s) on autopilot. This is when a person can receive new information at a fundamental level. But information can either be true and good, or deceptive and manipulating.
An individual who looks to an outside force,while potentially allowing smaller intrusions in, may also be led by communicated instructions to avoid possible intrusions while in an internally-vulnerable state. On the other hand, an individual who does not look to an external force to take care of them and fight for them will develop an internal shield by which things cannot penetrate locally. The difference in these two shield types is that the former is less pressure and burdening locally, while the latter is a better local shield, but which also means local upkeep, and more penetration attempts. The other factor to consider with the latter shield type is a developmental deficiency.
When such a shield is made locally (such as those held by Roman soldiers), they could not be protected from behind. Roman soldiers could not be protected from above, or the ground beneath. They were capable of withstanding great blows directly in front of them, but were susceptible to attacks from many more fronts now further exposed due to lag time required for hefting the heavy shield.
Furthermore, an internally-developed shield leaves less potential for offense. Where there are great opportunities for an individual to go into the offensive who relies upon an external shield, there are less for the internal shield bearer. Tragically, one benefit leads to several detriments. It is not a hard-and-fast system though, as this analogical assessment is assembled… Someone trusting in an external shield (Deities, Civil Govt. etc.) could also hold a small internal shield, but would, by doing so, miss out on some of the beautiful encounters an individual might face in life. For after all, life is not only a battle to be endured, it is an adventure to be experienced!
Where a shield may keep out the bad, who is to say the good might not be barred from entry as well? Sometimes a risk in the way of some back doors is good for any stronghold. The worst scenario (in holding with a soldier analogy) is one where the one and only entrance has been penetrated, and the only escape is straight through the invading force. It means, of course, that there is a risk of the invading force to find the back door and covertly take the stronghold, but it also permits a covert exit for specialized individuals to observe the impending invasion from a unrecognized position. Where there is a risk, there is a potentially-great benefit.