brain in vatSkepticism refers to a school of thought categorized by rational doubt. In philosophy, the type of skepticism usually referenced is epistemic skepticism, which is what we will focus on here. This consists in doubting that we have knowledge about the world; in fact, it can even be viewed as asserting that we can’t have knowledge about the world. However, rather than actually believing this doctrine, most philosophers see skeptical arguments as signs that our theory of knowledge must be modified. Thus, skepticism is commonly used as a tool to test epistemological theories. I will presently outline some of the major skeptical arguments, the shared features of said arguments, and some of the ways philosophers have responded to them. This is my first post, so judge it accordingly 😛

Skeptical Arguments

The dream argument – I have had dreams before, in which I questioned whether I was dreaming, and became convinced that I was awake. After all, some dreams are so vivid that there is hardly any observable difference between the dream and reality. What if I am dreaming right now? I would, and do, have no way of knowing.

The evil demon (or genius) – What if there is an evil demon who is absolutely powerful, and is interested in devoting all of his energy toward deceiving me? He has shrouded the world in illusion, such that nothing I see is real; he has confused my mind, such that nothing I think is accurate; he has tainted my judgment, such that nothing I believe is true.

The brain in vat (BIV) hypothesis – What if a mad scientist has captured my brain and placed it in a specially designed vat? He has equipped my brain with wires that feed it information through electrical impulses; as parts of my brain are activated I perceive corresponding images, thoughts, and sensations. These reactions are what I think is reality, but the true reality is that I am merely a disembodied brain made the experiment of a scientist with questionable moral values.

Skeptical Structure

The essential skeleton of skeptical arguments runs as follows,
1. There is some possible scenario, such that it would be impossible to be sure that you aren’t victim to it.
2. In this scenario, your beliefs about the world are false.
3. Hence, it’s impossible to be sure that your beliefs about the world aren’t false.
4. Therefore, you don’t know anything about the world.

Countering Skepticism

Most philosophers want to defeat this argument by rejecting certainty as a necessary condition of knowledge. Those who do this are called fallibalists; they claim that knowledge only requires a sufficient degree of justification, not certainty. Precisely what this degree of justification is remains a matter of dispute. Hopefully a later post can offer the details of this debate, as it contains many of the most interesting ideas in epistemology, but it would be too much of a digression to describe it here any further. The main idea to note is that skeptical arguments merely show that we aren’t certain of reality, so by rejecting certainty as a condition of knowledge, we are able to know things despite these arguments.


It is easy to see how uncertain we are of the world around us. There are so many limitations of the human mind and body that can allow for considerable error. We can also learn from the skeptic and the advances in epistemology that skepticism has spawned. This is to say that, despite the destructiveness that being skeptical may seem to bring, it is ultimately criticism meant to improve our clarity, and therein, the truth. One should note here that trust differs from faith, and the lack of the latter doesn’t necessarily diminish the former. So next time someone argues with you (i.e. they are skeptical of your claim, whether tacit or otherwise), my advice is to view it constructively, you both may learn something. Anyway, I tip my preacher’s hat to you 😛 The dream has ended, wake up!

Posted in Legacy.


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