A GetWisdom member recently asked “how many dimensions there were? Fifteen?” Is a “dimension” defined more by what reality one can access, rather than the nature of energy itself? If Michael the Archangel can access more “dimensions” than Lucifer, is it accurate in a way to think that Michael has fewer boundaries to worry about, and therefore fewer “dimensions” for him than Lucifer has?

This is an interesting perspective that is accurate in a number of respects. The actual physics of this are more complex than you appreciate. This is a somewhat naive interpretation but at the same time has a deep awareness that there are distinctions to be made with respect to the so‑called dimensions and the consequences of their being defined because that presupposes limits and boundaries as well. When moving from one dimension to another there must be a change in the configuration of energies to demarcate that frontier and that border. It might be a rather ill-defined and gradual transformation and transition from one dimension to another but nonetheless represents a change in some way, and that can be definable eventually with clear distinctions in makeup and the set of possibilities one is a part of in the new dimension that has been entered. So in your question, you are mixing metaphors somewhat here. The fact that an archangel has a greater range of motion in traversing more dimensions than Lucifer, who is constrained within a very defined range of movement for purposes of containment, does not mean that the archangel does not differentiate multiple dimensions by being unrestricted. It only means there is a capability of movement and exploration that is allowed that is much vaster than for a dark being under constraint. So the differing dimensions traversed by Archangel Michael do represent energetically distinct zones having particular properties. The light being can traverse multiple dimensions with ease because their consciousness is fluid in the sense of being readily adaptable to many differing sets of conditions energetically in the environment. This is not true of the physical being, which is quite fragile and must be supported within a very narrow range of constraints of physical energy to maintain its integrity and function as an organism. Once you move beyond the physical realm into higher vibrational states, there is much greater fluidity but there can be constraints on movement based on limitations imposed by the divine under certain circumstances, or as a cautionary measure to demarcate areas that may be hazardous to the high vibrational beings because things are under too great a state of flux and there is a danger to energetic integration to venture too close to some natural phenomena, for example. But this is an example of why you are never done learning—the universe is vast and contains endless delights but as with the physical realm, there are phenomena that are more challenging for a particular mode of expression by an entity. So you simply must know what you are doing when you move out and about beyond familiar territory. That will always be true through your vast future. There are many new wonders to explore and all will bring great rewards but will have their demands as well for greater knowledge and wisdom.