Black holes are incredibly dense objects formed by the gravitational collapse of massive stars. They have an extremely strong gravitational pull, which arises from their immense mass packed into a very small volume. The gravitational force within a black hole is so strong that it warps the fabric of space and time, creating what is known as a singularity at its core.
In the context of a black hole, the term "falling into themselves" can be interpreted as the collapse of the singularity or the further compression of its mass. However, our current understanding of black holes suggests that the singularity is already at a state of maximum density, and it is not possible for it to collapse further within the framework of general relativity, the theory that describes gravity on a large scale.
At the singularity, the laws of physics as we know them break down, and our understanding becomes limited. It is believed that at such extreme conditions, quantum effects become significant, and a theory of quantum gravity would be necessary to describe the behavior of matter and spacetime within the singularity.
Therefore, from our current understanding, there is nothing that prevents the singularity of a black hole from "falling into itself." However, the details of what occurs within the singularity remain an open question in theoretical physics.