Also the one that isn't here quite yet but is likely to eclipse all of those things into relative insignificance, AI.
Real AI is not possible to create without replicating biological reproduction and evolution. There are two issues here: most organisms really are Freudian in nature and are not just spontaneously thinking for no reason, but more like problem solving things that are related to the prime directives they're built with - usually things like reproduction, shelter, food, etc. For instance, there is enough quantum noise and entropy floating around where a human could record it 24/7 and study it eternally, but they would not because there is no payoff related to their Freudian urges.
A so-called AI, on the other hand, would not have such Freudian prime directives and would get stuck in a hard loop doing things like just staring at random entropy forever. It has no such Freudian prime directives, so it's either going to have no motivation to perform any action at all, or it's going to get hard locked attempting to endlessly analyze every meaningless detail/noise/entropy that exists.
To create AI, you would be forced to give it some type of identical Freudian prime directives just like humans, such as reproducing itself or what have you. The 'AI' would then not get continuously hard locked doing seemingly useless things because the artificial Freudian instincts are it's debugging mechanism. You would likely still need to use magic numbers like: halt analyzing data after whatever numbers of seconds or power expenditure elapsed with no useful returns to operation.
Trying to create AI this way still wouldn't be real AI, you've just created some type of designer, seek and destroy, self reproducing robot that probably consumes all resources in the universe while obliterating anything that gets in it's way - a physical, macro-scale virus in other words. It's debugging routines, or artificial Freudian instincts - whatever you want to call them - also sit above anything it does in hierarchy, making it just a complex looping script or algorithm artificially designed by you.
A real AI would be required to be able to rewrite and create all of it's own debugging and prime directives that govern how it operates on the fly in order to not be considered a script. When you alter the base debugging code that governs how the entire system runs, some alterations would create hard locks because this process simply cannot be done without trial and error, or harnessing the power of entropy in an infinite monkeys with typewriters phenomenon until you get something that doesn't hard lock.
Since you're 100% guaranteed to have hard locks, it's impossible to proceed past this point without the action of the AI duplicating/copying itself each time it attempts to perform said action. The old and new copy would then exist in the same physical plain of existence and be forced to compete with one another for resources, thus you have seemingly replicated biological evolution/natural selection, just in the form of silicon. This form of silicon evolution could pass by much faster than biological evolution, or another possibility is that while the silicon entities can theoretically rewrite their own debugging code and succeed, the chance is so small that every real world attempt fails and only the original, human created one remains which is just a complex script in practice.
As for the whole argument about whether humans are Freudian or not and entirely based around simple prime directives as discussed above, some will argue that since we perform numerous actions seemingly unrelated to Freudian directives that means we aren't. In reality, it's possible humans have just learned to harness so much energy and data/entropy streams from the environment, that we already are the advanced robots described here and can blow resources at random in any given direction to study and persue an infinite possibility of things while your brain has subconsciously planned that these seemingly wasteful activities unrelated to Freudian directives might occasionally have a payoff towards them.
TLDR:
Creating real AI is likely impossible because it requires a script performing a trial and error process that theoretically could succeed, but might consume more energy than exists in the universe before doing so.