Your childhood is the time when the foundations of the structure that will go on to become your personality are being laid down. This foundation, like a house’s foundation, needs to be ‘rock solid’ and the information you gather about the world at this time will then be laid down in a process that solidly cements this in to place.
And like the house then built on top, what is underneath will cease to be visible so that all you will see is the building itself with little or no indication as to the actual real state of what it rests upon.
If the foundations of a house are well made, that is constructed properly and made of the right material, then they sit well within the earth and hold the building up.
If they are less well built, perhaps the materials used are of poor quality and not up to the job or are laid down unevenly, then the subsequent building will not have a firm base. It may even remain standing for some time if there are no strong outside forces actioning upon it and the ground itself remains stable.
However few places are like that as the planet is constantly shifting and storms can rage and riverbanks overflow.
It doesn’t even have to be sudden events that can challenge the building’s structure. The action of gentle rain over long-term can wear away foundations just as much as a sudden storm.
Your foundations for your sense of who you are will have been laid down in direct response to your interactions with the people who were around you as you were growing up.
As you are not an ‘object’ like cement or a brick your own base will be comprised of psychological, feeling and relational components and the solidity of these depends entirely on the psychological, emotional and relational health of the people who were around you.
It is, however, possible to work on yourself and grow and change as an adult and rebuild your foundation - although it takes dedicated work as we are not actually designed to do this.