Positive atheism (also known as strong atheism and hard atheism) asserts that no deities whatsoever exist. Most believe who subscribe to positive atheism will say gods do not exist. Negative atheism (also known as weak atheism and soft atheism) is defined as a person who does not believe in any deities but they have a lack of positive believe, meaning they do not believe strongly in either existence or nonexistence of a god.
In modern times, theism has been defined for the most part to mean a belief in a god who gives personal revelations to humans, and a belief in a personal god who takes an active interest in the world. Now in this case a positive atheist will assert that he does not believe that there is any god or gods and he is also the type of person who disbelieves in a personal being who is completely good and who created heaven and earth. On the other hand, the negative atheist would simply be the person without a belief in a personal god. Another way the differences between positive and negative atheism can be looked at is from the point of view of implicit and explicit atheism. The terms were coined by George H. Smith. Smith defined implicit atheism as “the absence of theistic belief without a conscious rejection of it”. He defined explicit atheism as “the absence of theistic belief due to a conscious rejection of it”. To put in more simple terms explicit atheists have rejected the idea that any belief in a deity existed when they considered it. Implicit atheists have either not given much thought to the ideas of deities, or though they do not believe in any deities, they have not rejected the possibility of belief.
The definitions of atheism can also be considered from a scientific point of view. A positive atheists would assert since humans live in a scientific world where the existence of things exist solely by their observability, a deity cannot exists since it cannot be observed. A negative atheist would assert since we have no proof of god, we cannot be sure one exists.