Skepticism of Truth

Can We Reliably Know the Truth of Anything? Is Knowledge Possible?

Although there may be sound logical and pragmatic reasons for assuming that there are things which are true independent of us and our beliefs, we should ask ourselves whether that constitutes solid grounds for actually believing that truth is objective. Arguing that we don’t have such grounds is known as Philosophical Skepticism.

Richard H. Popkin and Avrum Stroll describe Philosophical Skepticism in their book Skeptical Philosophy for Everyone thus:

  • “What all forms of skepticism have in common are reservations about the attainment of knowledge. [T]he radical skeptic doubts that any piece of information is any better than any other. ...The mitigated skeptic disagrees. While concurring that certitude is unachievable, his outlook is that some information is more reliable than other information. Generally speaking, the mitigated skeptic is committed to the thesis that information is to be described in probabilistic terms. The more probable, the more reliable. But in saying this, he is also saying that no degree of probability, no matter how high, is equivalent to knowledge.”

Philosophical skepticism can be traced to some of the earliest philosophy of ancient Greece. One of the most influential defenders of the idea that truth is relative was Protagoras of Abdera. According to him, the fact is that our means of perception (sight, hearing, smell, etc.) are all limited and fallible.

Because of our ability to acquire information about the world is inadequate, he argued, we cannot be confident that our information is accurate — and in that case, how can we be confident that anything is objectively true?

Descartes formulated the two most powerful ways of expressing skeptical doubts.

The first is called the Dream Hypothesis, according to which “we cannot know at any particular moment that we are not dreaming.” The second is known as the Demon Hypothesis, according to which a malevolent demon might cause us to believe with absolute certainty things which are absolutely false. A popular reformulation of this is the “brains in vats” thought experiment in which we are all really just brains in vats with no genuine contact with a genuine outside world while mad scientists cause us to believe the most nonsensical things, all contradicting “real” reality.

How can either of those hypotheses actually be refuted? How can anyone prove that they aren’t really dreaming? How can anyone prove that the outside world exists and that one or all us isn’t experiencing a manufactured “reality”? This is the context in which modern philosophy works to try to demonstrate that reliable knowledge is possible.

Perhaps one of the most pointed rebuttals to skepticism was the one offered by Wittgenstein, who argued that such skepticism in essence proceeds from a position of bad faith. According to Wittgenstein, philosophical skepticism is a type of obsession because the skeptic never, even from the beginning, allows for the possibility of anything counting as evidence which might satisfy his doubts.

Thus, doubt is perpetual, and the activity of constantly questioning is ultimately pointless.

But, pointless or not, such questioning does go on and it has resulted in a great deal of philosophical debate over the centuries. As a consequence, many people have come to argue that truth isn’t objective; instead, truth is a subjective, relative concept. What is true for one person may or may not be true for another.