Actual 17th and 18th century philosophy is definitely dense, and full of jargon, and tends to make you feel like you've been sandbagged. They'll start out with a claim that's hard to disagree with, like "Existing things have the property of 'existence'." Then before you know it, they're claiming to have deduced the divine right of kings, the morality of capital punishment, and maybe the fact that there is a teapot orbiting Mars. (There, see, I'm making fun too. One just can't help it.)