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What is Scepticism?

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Welcome to another instalment of quick-fire philosophy! Every Friday we take a brief look at the life and thought of an important philosopher from history, and I offer a few reflections on their ideas. Today we’re looking at Sextus Empiricus, a Roman Sceptic philosopher who lived around 160-210 CE.

Who Was He?

We know almost nothing about the life and background of Sextus Empiricus. All of our knowledge of the man comes to us through the writings of his that have survived from the Roman era, in particular the eleven volume work entitled Arguments against the Dogmatists and Mathematicians and also Outlines of Scepticism, which is the main source we have for learning about what the Sceptics believed.

What’s the Big Idea?

The doctrine of the Sceptics centres around one key principle; that we cannot assert the truth of any proposition with any more confidence that we can assert the truth of a statement that directly contradicts it. Another related idea is that our knowledge of reality is always mediated by the bodily senses, so we are unable to prove things are one way rather than another.

The word ‘sceptic’ is of course still in common usage in the English-speaking world, and has retained much of the same meaning.

My Reflections

It seems to me that the key matter, when it comes to Scepticism, is understanding the difference between subjective and objective truth. If there really is a world that exists independent of experience, then we would have to say it exists objectively, and has certain characteristics that are real regardless of what we might speculate about them. Many modern scientists would argue this is the case.

Considering objectivity also brings up the question of the existence of God, because there is a strong argument that says moral judgments, such as what is good or evil, are only possible if God exists. While I understand this position, my argument would be that good and evil are ideas that always exist in the mind of a subject, whether that subject is a human being or a personal God. God can always change His mind about what is good and evil, so they do not have objective existence.

The position of Sceptics such as Sextus Empiricus has been criticised because we all seem to make value judgments as an inescapable part of life. So to argue that we can say nothing with certainty seems to contradict everyday human experience. Nevertheless, Scepticism brings into focus a matter at the heart of both philosophy and theology – the very existence of truth itself.

In next week’s philosophy post we’ll be looking at the thought of Plotinus, and his ideas about what constitutes the human person. If you don’t want to miss future posts, please consider subscribing. Thank you for reading!


  1. In physics, there an idea called the Copenhagen model that is based on the fact that everything you do not see exists in infinite modes of realities, and you only confirm it’s reality, for both subjective and objective truths, by direct observation. This means that we all live in our own separate realities. I’m pretty sure this originated from skepticism, and just like you said it’s is very criticized because humans don’t like knowing that we always live in uncertainty.

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    1. Very interesting, Kat! What you said reminds me of quantum mechanics and the way observation of waves and particles seems to affect their state. Though I’m no scientist, I find that really fascinating.

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      1. Yes, it’s called wave-particle duality. Which means, depending from which point of view you observe something, it can behave as either a wave or a particle. Even humans can be made out of waves depending on how we look at it and which scientists we believe. I’m very interested in how physics applies to philosophy, and I’ll probably make a post about that soon.

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  2. Very interesting. As you alluded, this philosophy seems to want to dismiss objective reality or truth. It’s like he captured a half-truth. Works really good in some situations! But we may stay stuck in our own heads, not able to fully embrace the transcendent, just to dismiss it as unknowable. We may end up lost in the morass of doubt and subjectivism. On the other hand, even our understanding of the objective can be quite subjective. So, we should not be so dogmatic either.

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    1. Hi Catherine! Thanks so much for your enthusiasm, but these posts are only meant to be a taster. It takes quite a lot of effort to keep them short and sweet! It’s cool that you want more, though 🙂


  3. Good and evil are defined by God’s nature, not His opinion, so the only way for God to change His opinion of good and evil is to change His nature. Is that possible? 🙂

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      1. Sure. God’s nature is love. Everything defined by God as good or evil emanates from that nature. Those acts or thoughts that contradict God’s pure, unadulterated love nature are evil, or tainted at best. We have various lists in the Bible of acts that are generally considered evil, because they nearly always violate God’s love nature, and other acts that are usually “good” because they mostly agree with God’s love nature. I say usually and mostly because God judges the motives and intentions of the heart. God’s own motives and intentions always spring from His love nature, but ours don’t.

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        1. Thank you, Don. I’m interested by the fact you say ‘God judges’, because for me judgment implies decision-making concerning what is good and evil. So God chooses the rules, rather than the rules being somehow objective. I think that’s what I was trying to communicate in the post 🙂


          1. Thanks, Steven. If I could clarify just a bit… Even God’s judgments flow from His unchanging nature (love) and so they are also consistent and unchanging. That’s why God cannot “change the rules” or redefine good and evil. These are defined by an unchanging, objective standard – God’s nature – and His judgments regarding good and evil always flow consistently from that same nature.

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            1. Thanks for the clarification, Don. I’m not convinced that the events of history, and in particular the Christian gospel, are things that had to happen because they somehow flow from God’s nature. I think God determines what happens, rather than it happening by necessity. I see God as actively unfolding all events, whereas you seem to be arguing that God is constrained somehow to only act lovingly. I don’t believe God is constrained, but makes choices. He may choose to act lovingly, but He certainly doesn’t have to.


  4. I think that summarizes a key difference in our perspectives. I do believe God chooses to act, but He cannot contradict His own nature, meaning that He cannot be or act as something other than who He is. That is why all of His actions and judgments originate in love. As for the events of history, I don’t believe they had to happen. God definitely chose to initiate this creation, but He did so out of love, which is a major theme not fit for a mere comments thread! 🙂 Maybe I’ll post something to elaborate on this. If you believe that God is responsible for all good and evil alike, I can see why you’d disagree that God always acts lovingly, but by believing that God’s essential nature is love (1 John 4:8) I propose that evil acts don’t originate with God, although His response to them always flows from love (e.g. “while we were yet sinners, Christ dies for us”).

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    1. Hi again, Don! Thank you for your explanation, which I think helps to clarify things. Yes, I certainly believe that all things are under God’s control, and originate with Him. I find the idea that God is in control of all the good stuff and none of the bad stuff highly problematic, as He would be moving in and out of our lives (and creation) in a way that to me seems impossible.

      You’re right that we can’t cover everything in depth in this comment exchange. Readers can explore my Theology posts for my perspective, and if you do post on the subject feel free to drop me a link to your post as I’d be interested to check it out 🙂 Interesting discussion, thanks buddy! 🙂


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