Wisdom includes perceiving reality correctly. I believe Ra is correct by calling our world an illusion. That things like deterioration, entropy, disease and death are like a fabricated trick for the purpose of growth and development of civilizations and of souls instead of something natural.
This means that the philosopher’s stone is a huge leap in how reality is experienced. For example I take the claim that the philosopher’s stone gives immortality literally. In this view third density is obviously an illusion in the sense that immortality is almost unimaginable for us to think of, even scary.
Then what about fourth density, is there death still in fourth density? Here is what it says in the Law of One:
43.11 Questioner: What is the… can you even state the average lifespan in the fourth density of space/time incarnation?
Ra: I am Ra. The space/time incarnation typical of harmonious fourth density is approximately 90,000 of your years as you measure time.
Let’s think this through. Does living a life of 90,000 years make sense from our third density perspective? My claim is that no, it doesn’t. At least not in the sense of being born and then gradually grow from an infant to a toddler to a child to adolescence to adulthood to old age and then death. Imagine being a child for 10,000 years, what a nightmare. Or living in old age for 20,000 years and slowly getting sicker and sicker until death. Not good.
Instead I believe Ra is pointing out that fourth density will last around 90,000 years, not that we will have third density bodies that will age and die for such a long span of time.
"I declare to you, brothers and sisters, that flesh and blood cannot inherit the kingdom of God, nor does the perishable inherit the imperishable. Listen, I tell you a mystery: We will not all sleep, but we will all be changed— in a flash, in the twinkling of an eye, at the last trumpet. For the trumpet will sound, the dead will be raised imperishable, and we will be changed. For the perishable must clothe itself with the imperishable, and the mortal with immortality. When the perishable has been clothed with the imperishable, and the mortal with immortality, then the saying that is written will come true: “Death has been swallowed up in victory.”[h]
“Where, O death, is your victory?
Where, O death, is your sting?”[i]" - 1 Corinthians 15:50-55 (NIV)
h. Isaiah 25:8
i. Hosea 13:14
In alchemy there is for example this picture which looks to me like symbolizing the death of death.
“The black sun as pictured in the Putrifaction emblem of Philosophia Reformata (Johann Daniel Mylius)” - Wikipedia