Science of Heaven
He was an atheist. His sons are atheists. He supposes that most of Amestris leans toward agnosticism and that only the privileged—if one can use that word—few even realize that something calling itself God reigns and deigns high above matter and mortals.
Hohenheim's youth (he pegs it between age 5 through 100) was immersed first in bondage and then in the science that freed him. As such a man of formulas, theorems, measurements and elements, he did not choose to dwell upon the grinning but otherwise featureless being at alchemy's gate.
Growing old well past natural human ages changed him through experiences and thought processes that were rehashed over and over in his memories. The world was not as black and white as the science would sketch it. The world was full of colors, wonderful and terrible shades that proved to paint beauty on the canvass of life. He became open to every possibility.
Religious lore passed down through millennia had become logic. If there were a God, and he held such power as the ancient texts exemplified, he had a dwelling place (a grand affair that outshined the palaces of Xing if the scribes are to be believed.) Logic carried him further. If this God created everything from the hands he clapped to the ground Trisha was buried in, surely God's house was an abode for human souls: Heaven.
It was an unsettling principle to drag his mind through. He could not prove or disprove it. Hohenheim could only reason that if the soul becomes separate from the body at death, its ultimate "homecoming" would return the soul to its origins.
These thoughts accompany the lonely train trip back to his wife's roots. To his sons' roots, he tries to remind himself. It is futile because they are alive and in wise, loving hands. Trisha is still waiting.
Hohenheim watches the hills that look blue in morning twilight roll by as the train breaks slowly beside Resembool's station. He steps off wearily. His right hand feels strange without the weight of a suitcase he no longer needs.
'I'm almost home.'
His memories know it and they sift through all 450 years to rest on the special moments lived (and relived over again in his mind's eye) with Trisha Elric.
"I'm sure we can change. Because we're weak. And because we die. We have to fight in order to live, and that's what will make us strong."
"Where does the other half go? Chop firewood, eat my cooking, and we can call it even."
"I don't need a ceremony, but some flowers would fit nicely with the cake."
"Those toys are a bit more eccentric than the roses you whipped up earlier, but if Edward likes it, I suppose."
"He needs a brother. He and Winry both need a mediator."
"But no matter how I end up looking, I'll always be happy to take a picture with the family where everyone is smiling."
"I'll be waiting."
He finds himself at the cemetery gate and unlatches it as carefully. The gate squeaks sharply as it opens but otherwise no disturbance is made in the approach to Trisha's grave. Hohenheim observes with an unsurprised but wry thought that his sons ensured the absence of religious ornaments to honor their mother.
He kneels and wonders –had he the strength left to do it—if she would appreciate a final bouquet from her husband. He'd missed the funeral and had never placed one at the grave.
"I'm sorry, but I'm dying first."
Hohenheim realizes that death is harder than it appeared to be through all the decades gone by seeking it. He does not understand where he will go; no equation will reveal that. Will he see Trisha again? Can he apologize for leaving his wife and sons behind? Are his words resonating somewhere science hasn't ventured, or are they forgotten in the morning solitude?
Perhaps in his last moments, during his last words, his mind was still trying to piece together the mystery. Alchemists were hopelessly stubborn in that way. He thinks of the invisible but very real presence of the spirit; how it linked body and soul. He pictures the blindingly white being who had now rightfully repossessed his gate. He sees his wife's glowing silhouette, brighter in death than the rising sun at his back.
He closes his eyes and decides that if nothing else, Trisha didn't need any more flowers. She was surrounded with them and waiting, smiling, reaching. The science of heaven could be discarded for the fervor of that sentiment.