An “idea” in this sense is a technical term, meaning some discrete thing in the mind. Berkeley’s metaphysics began with the assumption that all we ever know are our ideas, which are in our minds. (This is one reason why ideas are so important.) We tend to assume that if we have a word for something then we have an idea of it. But sometimes we fool ourselves, and our words are just empty with no ideas behind them. Therefore, we need to make sure that we actually have the ideas we think we have. Just because we are accustomed to using language in certain ways, does not mean that all words that are intelligible to us refer to ideas. If we reflect on abstract, general words, such as “man,” “whiteness,” “animal,” or “matter,” it becomes evident that there is nothing in the mind to which these words refer. All of our ideas are about particulars or combinations of particulars. We lack the capacity to create new ideas—only God can do that—although we are able to combine existing ideas in new ways and create copies of existing ideas.