Many atheists proclaim with confidence that nothing happens after death, or rather that there simply is nothing after death. That all that awaits is an eternal nothingness. I’d argue all people, religious or not, should be scientific when it concerns the world we inhabit, and those who argue boldly that there is no god should be scientific most of all. If we are to be strictly scientific, then evidence points towards reincarnation being the most likely outcome.
A scientific view is one of materialism. In other words, the physical world is not directly influenced by anything outside of it (unless you consider brane cosmology, but even then, if hyperspace is confirmed to be real, our definition of physical reality would simply extend to include it). This means taking the stance of souls not existing, and god not having direct influence in the world. In such a material world, we have to answer the question of “What is consciousness?” the hard way. Some may say that it is a result of the brain, or even just a small portion of the brain, but the true answer is that it is neither. There is nothing inherently special about the neurons that make up your brain in the same way that there is nothing special about the cells making up your hand. Every cell in your hand has been replaced at one point, in a manner akin to Theseus’ ship, and yet it is still your hand. Similarly, you could replace all the neurons in your brain, but as long as they behaved in the same way and were set up in the same arrangement, you would still be you. In other words, it is the specific configuration of neurons rather the neurons themselves that make you. One way to think of it is like a circuit. Regardless of whether you use one wire or another, a circuit made to light a lamp is still a circuit that lights a lamp, and if you remove any of the necessary components (such as the lamp), it by necessity becomes something else entirely. But that is only part one of the puzzle.
The second part, and the most important, is that there is tangible evidence for coming into life from death. We have all experienced it. Before we were born, we were dead. In math, and logic in general, all that you need to disprove a statement is one single counterpoint. The shortest academic paper ever written is a famous example of this.
If one is to say that death is the end, then they are objectively wrong as death is where we have all come from, and if it is possible to change from a dead state into a live state once, then it can happen again unless a new condition makes that impossible. If we were approaching the end of the lifespan of the universe, then perhaps a more convincing argument for death being the end could be made, as no new life would be able to come into being, but even then, until we know that this universe is all there is (brane cosmology says hi again) then it is still not a definite answer.
Just as the same computer can be built again, the patterns in our brains that make up the phenomenon known as our consciousness will inevitably form again and again given enough time, bringing us back into material reality. That is, unless an eternal heaven, hell or wherever else are real and we do have souls. Buddhist cosmology accounts for non-eternal heaven and hell realms which are fully possible in our reality, as long as you think a utopian society can exist (and we already have examples of hell on earth). If there is an argument to be made against suicide for the atheist, it is that you may find yourself in a new vessel where excruciating pain and suffering is more common than it is here and now.
Some may argue that you are not yourself if you do not retain any memories or life experiences, and if that is your stance, then I will concede that my line of thinking will not convince you, but I will invite you to research the Buddhist idea of no-self. If there is a flaw in this argument, it is in the thought-experiment of two of you existing at the same time. Take, for example, a clone. You simply can’t be conscious in two places at once, can you? With all that said and done, I’ll take the easy way out and choose to believe in the existence of a soul.
