My eyesight is failing fast. For years I have had both macular degeneration and glaucoma, but my eye doctor and I have kept them at bay with twice-daily drops and special vitamins. Now I’m having more trouble reading and watching TV. Two of my near ancestors were blind in old age. So I’m thinking about what my life will be like if my sight goes before I do. Writing is what I would miss the most; it’s how I think, maintain my equilibrium, make sense of life or concede that I can’t. I’m so used to finding words for my thoughts and reading them back that I don’t know how I could remember them otherwise. And that’s not even talking about the lists I jot down every day and depend on to organize my life.

Of course something else may overtake me before blindness does. All of my systems are faltering—digestion, hearing, memory, mobility. Given that array of things to worry about, and my lack of power against them, it has seemed best to go on doing what I’ve been doing: ignoring the portents and getting by.

However, I’m paying more attention to the chemistry of food and sleep, weather and worry, exercise and human conversation, all of which affect how I feel from day to day. Most of all, I’m intrigued by the things I’m learning, from a number of sources, about the malleable human brain. So much of what deters us is unnecessary, built into our minds early in our lives by random incidents and influences we had no way to judge. So many old hurts can be healed, so much in our present beliefs about life and about ourselves can be improved even into old age, by teaching the brain new things.

But some of science’s new truths are ambiguous. For instance, while our brains can needlessly alarm us over dangers that aren’t really there, they can also protect us from getting too upset about realities that are. So is my brain protecting me from truth I couldn’t bear to know?

That could account for my surprising new acceptance, this kind of dreamy walk through the ruins of my world, my impending loss of everything. Of course I know that I am going to die. But there always seems to be a flashlight’s-length, or perhaps a streetlight’s circle, of remaining time that I can count on.  I don’t want to think of what is beyond it. Yet it may go out at any moment, and I’ll be ambushed. I may not even know it has happened, and somehow that thought is the hardest of all to bear.