What We Are

What are you? What are humans? (one might ask the same about birds...)

Each human is an extremely complex chemical system. They are one of the many results of a few billions of years of biological evolution.

Metabolism, beginning of life
[link 1][link 2]

The beginnings of life are probably (in an abstract way) very similar to our own lives today: needing the right resources and energy gathered and arranged in the right ways in the right process sequence.

See also: a lot is due to Naturalism being true

Evolution
Evolution is logically inevitable for any entity that has the following three properties:
 * 1) self-replication
 * 2) variation in offspring
 * 3) external conditions for survival

Self Replication:
Countless events happened in the early days before and during the formation of life, just as today, that essentially didn't matter long-term. Sure, they might have mattered for a while, but then the end came for them.

What we see today is the result of the other things, the things that lived on. The things that aren't over.

By whatever luck or statistical inevitability, some of these trillions of trillions of events had the result of causing a similar seeming event to occur again. Which means this chain of (seemingly) repeated cause and effect could continue.

Variation in Offspring:
But these seemingly similar things were not always identical.

In the early days, the molecules may have been small and simple enough that true perfect replication of molecules could happen. But even then, there would be variations in temperature (which is speed, vibration, rotation) and bending.

Perhaps more importantly: everything else around the entity. If two identical entities are put into different contexts, a different result can happen. And it's hard for this to not happen in the natural world. The earth was never identical over every square inch, and the movement of molecules, through natural "Brownian Motion" never led them all down the same path of motion, or caused them to collide with all the same types of other molecules in the same order.

So variation seems inevitable in a natural universe. It takes work and effort to reduce it or prevent it.

External conditions for survival
Since outcomes are determined not just by an entity, but also by the entity's context, sometimes the outcome is that the entity is either destroyed or simply unable to reproduce itself.

Again there is some semi-randomness to the outcomes, but there will always be some physical sense to the results. We know why the forms of successful life forms can increase their chances of reproduction. The external conditions, and the interaction between the entities and their context, are not completely random. There is often a lot of similarity. Enough for certain forms to persist over time. But also enough differences and leeway for other successful forms to also persist over time.

Human-level intelligence
Our internal data processing can roughly be divided into System 1 and System 2.

System 1
I'm not sure if "information processing" is the right term to use for System 1 stuff. Obviously, it does process information. But we usually instead call system 1 stuff: skills (including social functioning), virtues, values, experience, memories, intuition, feeling, perception, personality, and that sort of thing.

Learn-able system 1 things are only learn-able from experience. Though system 2 analyzable knowledge can help to prepare both the learner and the learning environment for a speedy successful learning process.

Pros and cons of system 1:
 * quick, immediate
 * doesn't require much effort or thought to complete, once you've acquired the skill or whatever
 * can produce consistent, reliable results
 * hard to change habits and such if you need to after they form
 * not directly analyzable, "unpackable"
 * can "feel" correct even if it's mistaken
 * less successful in new situations, unfamiliar subjects, skills often don't generalize

System 2
By system 2 information processing I basically mean analytical thought.

relying on direct experience, trial and error, results in too much unnecessary error. It's better to be able to predict errors before you even experience them.

why and how rationality is necessary and helpful, dangers without it, our brains are naturally flawed hence the creation of philosophy, we need to patch up these flaws to prevent and recover well from crises [link]