Link: A chronology of human evolution

Link: A chronology of human evolution

http://www.bbc.com/news/science-environment-34192447


Ardipithecus ramidus (4.4 million years ago) : Fossils were discovered in Ethiopia in the 1990s. Pelvis shows adaptations to both tree climbing and upright walking.

Australopithecus afarensis (3.9 - 2.9 million years ago) : The famous "Lucy" skeleton belongs to this species of human relative. So far, fossils of this species have only been found in East Africa. Several traits in the skeleton suggest afarensis walked upright, but they may have spent some time in the trees.

Homo habilis (2.8 - 1.5 million years ago) : This human relative had a slightly larger braincase and smaller teeth than the australopithecines or older species, but retains many more primitive features such as long arms.

Homo naledi (Of unknown age, but researchers say it could be as old as three million years) : The new discovery has small, modern-looking teeth, human-like feet but more primitive fingers and a small braincase.

Homo erectus (1.9 million years - unknown) : Homo erectus had a modern body plan that was almost indistinguishable from ours. But it had a smaller brain than a modern person's combined with a more primitive face.

Homo neanderthalensis (200,000 years - 40,000 years) The Neanderthals were a side-group to modern humans, inhabiting western Eurasia before our species left Africa. They were shorter and more muscular than modern people but had slightly larger brains.

Homo sapiens (200,000 years - present) Modern humans evolved in Africa from a predecessor species known as Homo heidelbergensis. A small group of Homo sapiens left Africa 60,000 years ago and settled the rest of the world, replacing the other human species they encountered (with a small amount of interbreeding).

A Hive Mind and the Myth of Free Will

Where does "me" reside among the billions of neurons? There's no single neuron that "me" lives inside of. The sense of "me" comes from an almost borg-like hive mind; the neuron collective, if you will. Choices aren't made by any single neuron firing. Many choices are made, but it seems to work by a democratic method: The most-common choice is the one taken.

When we journey below the neuron level to the atomic level, brains are physical mechanisms for making hive-mind decisions with. We also have our memories/experiences that are saved off to inform our future decisions. If our memories are what inform our future and at its root our brain is a decision-making device, it makes sense to think that our future decisions are not the result of free will. There may be an illusion of free will because we don't have instant access to all our past memories/experiences and able to spend time mulling over decisions, and our decisions have to be made instantaneously. In a sense, then, we can only make the decisions that our past experiences and memories tell us we should. If this is the case, then we have no free will. It doesn't mean that there's any conscious entity controlling us by marionette strings (unless by "God" you mean that we are our own God), it just means our past controls our present and from a mechanistic way of looking at it, we have no free will in those decisions. It's thanks to the hive-mind and the subconscious nature of those democratic decisions by our collective neuron firings that we get the impression we have free will.

However, knowing all that, we get along just fine in daily life as if we do have free will. It's like objective morality. There could be some objective standard for morality, but since that has to be filtered through the prism of our subjective experiences (including learning and biases), we can't be sure what those objective moral standards would be. The closest one can reasonably get is to generalize by using a 'least harm, most good' analysis and submit that to case-by-case questions.