Is Anything Certain?

Peter Unger maintains that all knowledge requires certainty. Moreover, since he insists that nothing can be known for certain, Unger concludes that “nobody ever knows anything to be so” (Unger, 42). This is Unger’s argument:

1. “If someone knows something to be so, then it is all right for the person to be absolutely certain that it is so” (42).

2. “It is never all right for anyone to be absolutely certain that anything is so” (43).

3. Therefore, “[n]obody ever knows that anything is so” (43).

Succinctly, nobody can know anything. As “anything” makes explicit, Unger suggests that we cannot have knowledge of our own existence, external objects, past or present experiences or even that 1+1=2.

He also insists that knowing anything with certainty is inherently dogmatic. Being certain involves a negative attitude; it implies that nothing (new information, evidence or experience) “will be seriously considered to be at all relevant to any possible change in one’s thinking in the matter” (44). Unger defines this as the attitude of certainty. This is why it is wrong “for anyone to be absolutely certain”. I agree with Unger and concede that (2) is correct.

However, Unger’s rejection to the attitude of certainty leads to the rejection of all knowledge. This is where Unger is an error. I intend to argue that premise (1) is dubious and that knowledge requires justified true belief but never certainty itself.

Before continuing, I must clarify Unger’s notion of certainty. Hitherto, I have used Unger’s notion of certainty (denoted in italics) without explanation. Certain is an absolute adjective analogous to the concept of flat. An absolute adjective is or is not. A board, for example, is flat iff it lacks any changes in gradi...

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...nger’s first premise).

2. Knowledge is justified belief with confidence.

3. Being confident, but not certain, allows for changes in opinion/belief in the face of new information and experiences (avoiding Unger’s attitude of certainty).

4. Knowledge with confidence, but being susceptible to new information is not dogmatic.

5. People can know things with confidence without being dogmatic.

6. Therefore, people can justifiably and confidently know that some things are so.

The above argument allows for things to be known but in a non-dogmatic manner. Although, knowledge with confidence (but not certainty) can be considered a weak sense of knowledge, it avoids the skeptical conclusion while also avoiding Unger’s attitude of certainty. With the ability to amend and modify justified beliefs (knowledge), certainty is inherently absent from this notion of knowledge.