Existentialism is a modern philosophical belief, or theory, that is positioned upon the study of existence and of the way human beings find themselves existing in the world. The concept is that humans exist first and then each individual spends a lifetime changing their essence or nature. If you take this into account, then by the philosophical theory of Existentialism alone, you can determine that this object, this mass of cells, is, in fact, a human being. In fact, the philosophical theory of Existentialism is opposed to any doctrine that views human beings as the appearance of an absolute or of an infinite substance. However, Existentialism doesn’t give an approach to what is right or wrong. The notion of the ludicrous in existentialism differentiates with the claim that ‘bad things don’t happen to good people’; in plain English, figuratively speaking, there is no such thing as a good person or a bad person; what happens, well, happens, and it may just as well happen to a ‘good’ person as to a ‘bad’ person.
The Memory Theory, part of the three theories that make up the philosophical theory of Persistent Personal Identity, is another theory to consider when deciding what a human being is. According to John Locke, memory is a necessary condition of personal identity. He also suggests that the self is “a thinking, intelligent being, that has reason and reflection, and can consider itself as itself, the same thinking thing, in different times and places” and continues to define personal identity simply as “the sameness of a rational being” (Locke). Given this assertion, any change in the someone makes a change in their own personal identity, and any change in their personal identity states that the person has changed. Locke goes on to suggest that a human being’s personal identity stretches only so far as that human being’s consciousness. Locke also presents an argument which says, in order to be a self, one must be a thinking thing, and that because “consciousness always accompanies thinking” (Locke), the self with which one personally identifies.
The Body Theory, another one of the philosophical theories that make up the theory of Persistent Personal Identity, includes discussing the Brain Theory. The brain-swap experiment is a good starting point on discussing the Body Theory. Suppose a mad scientist captured you and Cristiano Ronaldo, a famous soccer player, and put the two of you inside incubators. One day, he decided to perform a dangerous experiment by swapping your brains, putting your brain inside Cristiano Ronaldo’s head, and his brain put inside your head. Are you now the famous soccer player Cristiano Ronaldo? Well, actually in a way, but that’s not important. What is important is you beforehand were not bodily continuous with Cristiano Ronaldo, nor was he bodily continuous with you. If the body theory is true, then you what not be equal to Cristiano Ronaldo. The problem is, you are equal to Cristiano Ronaldo. Therefore, the body theory is false, because it does not determine what a human being is.
The Soul Theory, another one of the three theories of the philosophical theory of Persistent Personal Identity, discusses the fact that humans have a soul and animals don’t. A person at one time is the very same person as a person at a later time if and only if they have the very same immaterial soul. Proof that human beings have souls is found straight out of the Bible. In Matthew 10:28, it says, “And do not fear those who kill the body but cannot kill the soul. Rather fear him who can destroy both soul and body in hell.” In Ecclesiastes 12:7, it says, “And the dust returns to the earth as it was, and the spirit returns to God who gave it.” Clearly, the soul is something that has no form, no shape, and isn’t made out of any certain material. No man could create something like this. The only way for any human being to have a soul is if God put it there. Animal lovers would argue that their pets or other animals have souls. However, this is not a valid argument. God prohibited the killing of another human being, but placed no such restrictions on the killing of animals. Even if animals had a soul, it would probably be different from a human being’s soul. Jesus saved the souls of man, not animals.
In my opinion, to qualify as a human being, you only have to have a soul. Only humans have a soul.