Occam's razor (also known as the "law of parsimony") is a problem-solving principle which serves as a useful mental model. A philosophical razor is a tool used to eliminate improbable options in a given situation. Occam's is the best-known example.

Occam's razor can be summarised as follows:

Among competing hypotheses, the one with the fewest assumptions should be selected.

In simpler language, Occam's razor states that the simplest explanation is preferable to one that is more complex. Simple theories are easier to verify. Simple solutions are easier to execute.

Occam's razor doesn't deny complexity, but it prevents you from filling in the blanks with complicated 'man in the sky' assumptions of why things are happening. Take for example a complex phenomenon such as murmuration of birds, the explanation with the least amount of assumptions is that the follow simple rules such as following their neighbour, as opposed some entity orchestrating the flock to form the complex patterns which would require many more assumptions.

See for a great description: https://fs.blog/2019/10/occams...