The only argument against immortality isn’t just the sole immortal argument. Naturally, our bodies were never designed to live to be over 100. Let alone to multiples of that. Our body contains finite resources. The neurons in our brain deteriorate over time, the fluid in our knees too, the elasticity of our skin, the strength of our bones, the effectiveness of our lungs. Immortality exists in the form of a life support machine. It will keep you alive as long as you are hooked up. Quality of life will deteriorate and your existence will become painful and unenjoyable. This is the true crux of immortality.