Teleology in the strict sense is a branch of philosophy that studies the final purpose or cause of the world and evidence of this purpose in the world's design.
It is most often invoked today to refer to a style of thinking that sees natural forces as being directed toward some sort of end goal or purpose. Teleology is the logical basis for creationism, such as the argument from design. It usually leads to pseudo-scholarly works of determinism, e.g., historical determinism, biological determinism, etc.
 Teleology and evolution
Teleological thinking is deeply ingrained in our culture. So even people who believe evolution is how we got here can slip into it. Beware any of the following in an evolutionary discussion, particularly if you hear them coming out of your own mouth:
- "Highly evolved" - evolution does not have directional heights or an aim in mind.
- "More complex" - the genomes reached their present informational content about 600 million years ago. All changes since then have substituted new complexity for old. There is no progress or direction.
- "Purpose" - this word may mean something if you're very careful indeed - a functional explanation rather than a historical one (e.g. "the heart's purpose is pumping blood") - but can fail to communicate to your audience that it got this way by shit just happening.
- "The next stage of human evolution" - problems here are the words "the" and "next". Whatever happens to humanity will be shit just happening.