Dabbling in metaphysics

Here are my attempts at delving into deeper thoughts.


Humanity

What constitutes humanity? Biology? What separates a human being from an animal? Is it the superior ability to think and solve problems? Let's look at these separately.


The Ship of Theseus

If a person loses his arm, and has it replaced with a prosthetic (let's say a robotic arm -- I like science fiction), is he still human? The answer is probably yes at this point. There are people who don't even have arms, and yet nobody with a sane mind would think that they're any less human.

Now consider a person who replaces not only his arms, but his legs, body and face with artificial, robotic prosthetics. Since it's hypothetical, assume he keeps his brain, and the prosthetics allow his brain to function normally and control the movement of his body. Is he still human? That's slightly more debatable, as without the prosthetics, he can't survive -- he's anatomically more robot than human. But you may argue that as long as his brain is able to function, as long as he can think and act according to his own wishes, he is human.

Let's go to the extreme. Suppose we invent nanomachines that can emulate cells. Suppose a person loses his arm (again). His arm is replaced by one made from these nanomachines. Still, no different from the earlier example. If everything except his brain is replaced, it's still the same as before. Still human.

What if the poor chap damages half of his brain, and has that part replaced by nanomachines? Let's assume for now that in this hypothetical case, the nanomachines replicate human cells completely, so it is of no difference to the person whether the cells in his brain are actual cells or nanomachines. Is he still human? Following the previous logic, his brain still functions; he still acts human. He still has all his memories; still capable of feeling emotions. In fact he doesn't act differently at all. So he should still be a human, don't you think?

Now we go to the final extreme -- the other half of his brain is damaged and gets replaced with nanocells. Again, following the previous logic, he should still be human. But here's the problem. We have replaced his entire body with nanomachines. This body is no different from a robot that was created entirely out of nanomachines from scratch. Would you call the robot a human?


Free will

An argument could probably be made that the person fully replaced with nanomachines is not human because he has no free will. The free will he does have is an illusion because he is relying on machines to think and act. There are some problems with that.


Cause and effect

Digressing slightly, let's consider a simple concept. Cause and effect. An occurence is always caused by something. If you drop a glass, it will break. If you touch a thorn, you will get hurt. If you bang your head on the wall, you will also get hurt. The cause of your head hurting is banging it on the wall. The effect of banging your head on the wall is your head hurting. Simple concept.

The fact that there is cause and effect means that there are laws that govern the universe. Nothing happens out of random. There are causes for every effect.


Determinism: Hard and soft

Okay, so if there are definite laws that govern the universe, a cause will always produce the same effect under the same conditions. Say I drop a rock from a certain height onto glass and the glass breaks. If I replicate the conditions exactly (same height, same air resistance, same type of glass, etc.), the rock will always break the glass. That's hypothesis number 1.

Hypothesis number 2 is that all the things in this universe are governed by the same set of laws. Apples are governed by the same laws that govern oranges. While apples may look different from oranges, if you magnify the both of them, you'll see that they both consist of atoms. Magnify even further, you'll see electrons, protons, neutrons. They're both fundamentally the same (only different structurally), and as such they are governed by the same laws.

Now, if you magnify your brain, you will also see electrons, protons and neutrons. Brain is matter. It is also governed by the same laws of the universe.

A person's mind resides in the brain. It is the mechanisms in the brain that give rise to the concept of a mind. As such a person's mind is also governed by the same laws of the universe.

This means that a person's mind is also subjected to cause and effect, and effectively, a person's will is subjected to cause and effect. The implications of this is that a person's "free will" isn't so free after all, but rather an illusion that is created from a variety of causes (experiences, upbringing, genetics, etc.).

In this case, there is no difference between human cells and the aforementioned hypothetical nanomachines, if free will is an illusion created by human perception.

That's the basis of a branch of metaphysics called "hard determinism". There are a few problems with this. Morality is one. If a criminal has no free will, then he should not be held accountable for his crimes, because he cannot help but commit the crime.

There are several alternatives to this theory. One of them is called "soft determinism", which asserts that an act can be both causal and free. The fact that an act was caused does not mean that the act was forced. The distinction between a free action and a forced action lies with whether or not the act was voluntary or involuntary. If I choose to stand up, that action may be caused, but I was not forced to stand up -- it was voluntary. On the other hand, if someone points a gun at my head and asks me to stand up, then it is involuntary.

The second alternative to hard determinism is called "predeterminism", which rejects the concept of cause and effect in the first place. Predeterminists argue that the effects of some causal laws cannot be predicted precisely (Heisenberg's uncertainty principle), and mechanical causality applies only to things, and not people (link).


I think that's enough for today.