You need eyes to see. Ears to hear. Skin to touch. A mouth to taste. And a brain, to process it all. If the soul exists, it is not--cannot be--physical. All theologians must agree. So why is it, then, that we insist on assigning our experience as physical beings to post-physical life? Part of the reason is that it's easier to think of our own mortality through that chosen lens. Our physical lives end. There are no exceptions, despite best attempts by science and fiction. When our bodies die, if we have souls or energies or however you best like to think of it, there is an implied existence but it cannot be be as we perceive our physical lives. Has energy ever written a book? Kept a blog? Listened and wept to Beethoven? Been seduced by the dance? Is there a market share for souls? Do advertisers worry how energy perceives their commercials in order to boost sales? Does a soul stand? Eat? Sit? Drink? Without a body, how can it?
True, there is much beyond our imaginings as humans, confined as we are to physical limits. There may be more to the life of energy, to the life of the soul, than we can know. All we do know is that for unpredictable number of rotations around the Sun, we are physical. We can find meaning in our own physicality and the physicality of others and the natural world. We can find joy and pain, pleasure and horror, love and disgust. We look for "soul-mates" to define our physical lives even further, even though a great majority of humans place a very high value on physical chemistry in order to identify these supposed mates of the soul. As we age, our physical bodies begin to show signs of withering, of our impermanence. And we then begin to invest our physical bodies and physical monies into material items that make us feel more secure in our own physicality--things like clothing, jewelry, shoes, make up, boats, houses, cars, and a plethora of other items that bring us physical comfort, or that decorate, enhance, or otherwise celebrate our physicality. We use our investment in our physicality for sex, a physical act, that can produce other physical bodies we call "children." And children are a way to manifest our shared genetics, the building blocks of our physicality, so that some piece of our physical selves continues on into some imagined eternity.
As a society, people spend millions, billions, on the upkeep of their physical selves--a body that in the span of less than ten decades--dies. Withers. Decomposes. And eventually, disappears from physical existence altogether.
The strong evidence above is proofre's strong evidence that our existence is defined by, and is therefore meaningful because of, our physicality. So how and where does Nihilism fit in?
Because, once your physicality has ended, whether through natural death from old age, cancer, a car accident, a freak accident, an act of God, or the musings of a mad man, the meaning of your physical existence has ended. Gone. Never to return. You can never speak again. Hear again. Think again. Write again. Whatever you accomplished before your physical end, unless you painted a Monet or sculpted the David or wrote Moby Dick, goes into the human-ether, remaining in the consciousness of those who knew you until their physical deaths. If you're lucky, your physical image will remain important to some of your future generations. You'll be a distant thought until too many generations pass. Your grandchildren are gone and their grandchildren know only half-truths, if anything at all. When your photo is found in its dusty frame, the last vestige of your physicality, will it be recycled? Sold to an auction house? Used in a school project that ends up in a basement somewhere? All the things you did--the good, the bad, and the humanly ugly--will have been long forgotten. All the things you learned on your journey as a human being, lost in the annals of time and space.
Is life meaningless? Not while you're in it. While you're in it, you assign yourself more meaning than you're likely worth. You assign your material items value, then, insure those values to even further prove the unprovable: You, and your physical life, matter.
Take it one step further: Let's say that while living our physical lives, we connect at the soul as well. If you do harm, you hurt the pool of collected souls or energies that some think of as God. If you do good, you improve it. That would certainly equate to our perception of physical justice, but how can there be an eye for an eye if we no longer have eyes? How can we turn the other cheek when we have no face?
We can only prove our physical existence. There is no evidence that said existence has implied meaning outside of our physical selves. You can point to any religious texts you want; ALL were written by humans in the midst of their physicality. Which means, ALL are skewed by that same physicality.
Essentially, we know we're here. Right now. And that is all we can ever truly know. What happens after our physical lives end, if anything, is a guessing game based on presumptions, assumptions, and suppositions. Would you define your life by a supposition? Make an assumption your mantra? Use a presumption as the rule of law? OR, would you use what you know to be true as the basis for your life? To live fully and well while you may, as there is no evidence that life as we know it continues after our physical bodies die?
The idea behind Nihilism isn't that life is meaningless so you can do whatever you want--it's the exact opposite. Be self-responsible, be caring, be generous, loving, kind while you can. You will not get another opportunity. The people you encounter will die along with you. Even if reincarnation is true, you will never live this same life again. You only have one chance to do the right thing--for yourself, for others, for the world. If life only has meaning while you live it, why would you choose to do otherwise? And though there is an abundance of humans who refuse to acknowledge the truth, that's not your problem. Your problem is living your best life and living it now. Not tomorrow. Not in Heaven. Or Hell. Or wherever you believe you may go after your physical body has found its end.
And without excuse.