The French materialists believed that there is only matter, and believed that there is no spiritual element in the universe. They also concluded that man was like a machine, and that man is thus not morally responsible for their actions. They also concluded that man should aim to maximize pleasure.
In his book The Wealth of Nations, Adam Smith explained something called the principle of the invisible hand. Smith said that since people want to produce that which is monetarily profitable, they will want to produce what the customers want to buy. Smith said that because of this principle, no one has to be in charge of the economy. He said that people want to do what benefits them, but what benefits the people only comes about by giving benefits to the customers, so it is in his interest to help the customers.