Of course there are a few different ways to define "mechanical", but for me, it's been the best way to go. I develop, manage and trade 100% mechanical systems for the S&P E-mini and have been more successful with less stress for years because of it. Mechanical systems are not meant to "take the mind out of the trader", it just means that there are set rules to use, and there should be no deviation from those rules. Whether you auto-execute or just manually trade a mechanical system, you'll probably be better off for at least finding out why these methodologies can work for you.