I somtimes hear about Weak Atheism and Strong Atheism. What is the difference between the two?
Atheism is commonly divided into two types: strong atheism and weak atheism. Although only two categories, this distinction manages to reflect the broad diversity which exists among atheists when it comes to their positions on the existence of gods.
Weak atheism, also sometimes referred to as implicit atheism, is simply another name for the broadest and most general conception of atheism: the absence of belief in any gods. A weak atheist is someone who lacks theism and who does not happen to believe in the existence of any gods no more, no less. This is also sometimes called agnostic atheism because most people who self-consciously lack belief in gods tend to do so for agnostic reasons.
Strong atheism, also sometimes referred to as explicit atheism, goes one step further and involves denying the existence of at least one god, usually multiple gods, and sometimes the possible existence of any gods at all. Strong atheism is sometimes called gnostic atheism because people who take this position often incorporate knowledge claims into it that is to say, they claim to know in some fashion that certain gods or indeed all gods do not or cannot exist.
Because knowledge claims are involved, strong atheism carries an initial burden of proof which does not exist for weak atheism. Any time a person asserts that some god or any gods do not or cannot exist, they obligate themselves to support their claims. This narrower conception of atheism is often thought by many (erroneously) to represent the entirety of atheism itself.
Because strong and weak atheism are often called types of atheism, some people develop the mistaken idea that these are somehow akin to denominations of atheism, not unlike denominations of Christianity. This serves the bolster the myth that atheism is a religion or a belief system. This is unfortunate, in particular because the label of types is not entirely accurate; rather, it is simply used due to a lack of better terminology.
To call them different types is to imply on some level that they are separate a person is either a strong atheist or a weak atheist. If we look more closely, however, we will note that almost all atheists are both on various levels. The primary indication of that can be seen in that the definition of weak atheism, lacking belief in the existence of any gods, is in fact that basic definition of atheism itself.
What this means is that all atheists are weak atheists. The difference, then, between weak and strong atheism is not that some people belong to one instead of the other, but rather that some people belong to one in addition to the other. All atheists are weak atheists because all atheists, by definition, lack belief in the existence of gods. Some atheists, however, are also strong atheists because they take the extra step of denying the existence of at least some gods.
Technically, saying that some atheists do this isnt entirely accurate. Most, if not all, atheists are willing to deny the existence of some gods if asked few only lack belief in the existence of Zeus or Apollo, for example. Thus, while all atheists are weak atheists, pretty much all atheists are also strong atheists with respect to at least some gods.
So is there any value at all in the terms? Yes which label a person uses will tell you something about their general inclination when it comes to debates about gods. A person who uses the label weak atheist may deny the existence of some gods, but as a general rule isnt going to take the step of asserting the nonexistence a particular god. Instead, they are more likely to wait for the theist to make their case and then examine whether that case is credible or not.
A strong atheist, on the other hand, may be a weak atheist by definition, but by adopting that label the person is in effect communicating a willingness and interest to take a much more proactive role in theological debates. They are more likely to assert right up front that a particular god does not or cannot exist and then make a case for that, even if the theist doesnt do much to defend the position of belief.