Sentio, ergo sum

Sentio, ergo sum

I want to challenge you to a journey.

It might be the most adventurous journey that you will take. And it might change your life.

Just like most life-changing adventures, you might have stumbled upon this one by mistake. You took the right turn in life (and on the internet) and stumbled upon my humble blog. Or maybe it was a calling. A calling that all people seeking something more, something ineffable, have. Like a distant song into the wind, something that you feel in the back of your head, unsuppressed by the highly intellectual chatter of your rational mind.

Maybe you are a teenager, looking to find something to replace the foregone magic of childhood and to better understand the world. Maybe you are a young adult, trying to make sense of a world that seems too alien and cold in just it’s plain scientific description; Perhaps you are a mature man or woman, with a background in science or philosophy, interested in the deeper understanding of reality, of the nature of mind and metaphysical revelations. Or you are a spiritual being, of any age, driven by curiosity and a critical mind.

No matter the case, welcome, Seeker!

This journey will be a bit different from any other journey you have been through, so far.

And that is because this one will be entirely inside your own mind. Together, we will wonder the thick forest of knowledge, the dark caves of hidden assumptions and the steep mountains of logic. And if we are lucky, at the end we will reach the summit of revelations, a place from which no man has ever walked unchanged.

But as any epic journey, this one starts with the hero – you, his trusted adviser – me and an episodic sidekick. And this episode’s sidekick is the father of western philosophy, the 17th century French philosopher, mathematician, and scientist, René Descartes.

“Dubium sapientiae initium. (Doubt is the origin of wisdom.)” ― René Descartes, Meditations on First Philosophy


Descartes taught us many things, from analytical geometry to mathematical analysis. But his greatest gift to humanity was his genuine and unwavering ability to doubt. To doubt things he was raised to believe, things he took for granted, to doubt even his own mind.

This, my fellow Seeker, is called Cartesian skepticism. And it represents the first step we must take in our journey. Like before any journey, we must first make sure we do not carry with us false assumptions and erroneous conclusions. We must first empty the basket, like Descartes once said:

“Suppose [a person] had a basket full of apples and, being worried that some of the apples were rotten, wanted to take out the rotten ones to prevent the rot spreading. How would he proceed? Would he not begin by tipping the whole lot out of the basket? And would not the next step be to cast his eye over each apple in turn, and pick up and put back in the basket only those he saw to be sound, leaving the others? In just the same way, those who have never philosophized correctly have various opinions in their minds which they have begun to store up since childhood, and which they therefore have reason to believe may in many cases be false. They then attempt to separate the false beliefs from the others, so as to prevent their contaminating the rest and making the whole lot uncertain. Now the best way they can accomplish this is to reject all their beliefs together in one go, as if they were all uncertain and false. They can then go over each belief in turn and re-adopt only those which they recognize to be true and indubitable.” ― René Descartes, Meditations on First Philosophy

And this, Seeker, will be your first test. You will have to cast aside all your metaphysical assumptions about the world, all the those hidden underlying things that you never critically thought of, like hidden pebbles in hidden pockets in your clothing and sewn within your vision of the world.

And together, we will then pick them off, one by one and analyse them critically, with the sole tools that we have – logic and critical observation.

Some things will feel really “common sense“, while others, you never thought about them. But don’t worry, I will be your guide. I only ask of your openness and willingness to critically analyze the implications of many things that you previously took for granted.

And since there is no other way to start a walk of a thousand miles, but with just one single step…

Let’s begin!

First question: What do you KNOW?

Okay, this may seem like a trick question. You surely know a LOT of things. By making it thus far on this post, you must be a curious and intellectually active person, and thus, you must have a large baggage of information about yourself, the world and everything else.

But let us forget EVERYTHING and use Descartes’ method:

  1. Discard all knowledge.
  2. “Pick up” only the things you are 100% sure of
  3. Define all the other fundamental assumptions about reality to be in accordance to (coherent with) the thing you are 100% sure of
  4. Where you need additional assumptions to build certainty for complex problems, try to limit the number of uncertain assumptions needed to limit the inescapable uncertainty added (similar to Occam’s razor)

To begin discarding everything we think it is certain about the reality, let’s use two of Descartes’ own arguments, with a few small twists:

The Dream Argument:

Think about a vivid dream that you recently had. When you were fully immersed into the action of that dream, did it felt real? Most dreams do. We only realize the dream was just a dream when we wake up. From within the dream, we cannot say it is a dream or a waking reality. Yet, in hindsight, their nature seems so different! One is a product of our minds, the other is the… well, reality.

Or is it? From within a dream, there is no difference between the two. Just as Descartes himself argued, from within the dream, there are no sufficient grounds by which to distinguish a dream experience from a waking experience.

This argument also knows another version, popularized by the famous entrepreneur and visionary, Elon Musk: That for all we know, we might be living in a simulated world, running on the hardware of another reality. Something akin to the Matrix. Although I think Elon’s argument is fallacious (for reason I will explain in future posts), I do urge you to examine the uncertainty posed by the dream/simulation argument.

The Demon Argument:

Not only that everything we know about the nature of the world might be an illusion, warns us Descartes, but our own thoughts and ration might betray us, just like our senses do. For this idea he constructed the metaphor of a cunning, malicious and powerful demon that could be manipulating, deceiving us and controlling our thoughts.

Dreams and demons meet halfway in sleep paralysis.


In modern days, we have even more to add to this line of argumentation. Some philosophers say that our own reasoning is predetermined by physical causality. That we might not have free will.

Our senses are not very dependable either. You need not be a scientist or philosophers to understand the implications of trivial optical illusions and hallucinations.

At this point, with both his sensory input and his own rational thinking under doubt, Descartes started doubting his own existence, until he had the epiphany that brought back the ONLY solid ground under his existential feet:

By reaching absolute skepticism and doubting his own existence, he proved to himself that he exists. If he hadn’t existed, there would be no entity doubting it’s own existence. Thus, he reached the famous:

Cogito, ergo sum. I think, therefore I exist.

Descartes said this is the only thing we can be 100% sure about.

But wait a second! Lets leave our sidekick one step behind and add an insight he hadn’t got at his time. Descartes might be dubbed the father of western philosophy, but he was not lucky enough to have access to eastern teachings, among which, meditation.

We do.

Regardless if you practiced meditation or not, it is rather common knowledge than when you meditate, your thoughts come and go, like clouds on a clear sky, but in time, you master the ability to be aware without thinking.

So, If thoughts are just content in the mind and not a fundamental property of the mind, it means that Cogito ergo sum can be more concisely and precisely rephrased as:

Sentio, ergo sum. I am aware, therefore I am.

And this, fellow Seeker, it is the only thing you can be sure of. Anything, I repeat, anything else is uncertain. Is there a world out there? Is it all just a dream? Are there other minds, or is it all inside my own? What is time? Is space real? Is there death after life or is it the absolute end? Any other imaginable question and any other answer we can fathom is uncertain.

Perhaps, at this point, you are confused. Or maybe you feel that a veil is lifting and it all makes sense.

Regardless, I want to congratulate you for making this first step. Next week we will continue our journey with an incursion into the philosophy of science: the scientific method, its benefits and its limits.

If you feel that I am wrong, that there is something amiss with the conclusion of this first step, or if you just wish to share your thoughts with us, please, feel free to leave me a comment and I will answer.

Stay curious and do not quench your thirst for knowledge, Seeker! Until next time.



"There is no wealth like knowledge, and no poverty like ignorance." - Buddha </p> Please share this article if you liked it.
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