Is Knowledge of Essence Required for Thinking about Something?

Lowe claims that having knowledge of the essence of an object is a precondition for thinking about it. Lowe supports this claim with roughly the following argument: you cannot think about something unless you know what you are thinking about; and to know what it is that you are thinking about just is to know its essence. I will argue that this line of reasoning fails because of an equivocation in the expression ‘what a thing is’ (and similar ones), which can be used to indicate the essence of the thing but also, more commonly, some description of that thing which is useful in the context to identify it. I will then consider some possible variations of the argument, both in its premises and in its conclusion, and I will argue that they either fail to produce a sound argument or they weaken the conclusion too much to preserve the philosophical interest of the result.