Category Archives: Science

What Is Consciousness?

In one of my previous essays, I described Jeff Hawkins’ theory of intelligence. This essay relies heavily on that theory–if you’re not familiar with it, I recommend you read my other essay first.

The question of consciousness–of what it means to be “self-aware”–is one of the longest-standing unsolved problems in human history. It has showed up in practically every field from philosophy and theology to literature and the arts to multiple scientific disciplines including psychology, biology, programming, and even mathematics. Like the nature of sleep and dreams, it is one of those tantalizing problems that has resisted all solutions for millennia, despite being a fundamental part of our daily lives. Yet intelligence was also considered such a problem, and Hawkins’ theory tied a neat bow on it. Might the problem of consciousness be similarly solved? Continue reading

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Why Do Mirrors Reverse Left and Right?

When you see your reflection in a mirror, why does your right become its left, but top and bottom stay the same?  I’ve seen this question answered a number of different ways, but the explanation that makes the most sense to me is also, I think, the simplest: mirrors don’t reverse left and right.  They reverse front and back.

Since “left” and “right” are subjective,[1] let’s simplify the discussion a little: imagine that you’re facing due north and there’s a mirror in front of you.  If you jump up, your reflection will also jump up–no reversal.  If you step one foot sideways, to the east, your reflection will also step one foot to the east: not reversed.  But if you step south, away from the mirror, your reflection will move north–the opposite direction.

The reason mirrors seem to reverse left and right, but not up and down, is because when looking at our reflection we automatically imagine ourselves in their position–that is, turned around both left-right and front-back.  This habit comes from a lifetime of interacting with other people and having to interpret their “right”, “left”, “front” and “back” in terms of our own.  When we see our reflection, we reflexively identify it as another person, identical to us in every respect, except with all their features on the “other side”–e.g., a mole on the left side of your face is on the right side from your reflection’s “point of view”.  But it is not the mirror that makes this transformation–it’s us, when we mentally turn ourselves around and put ourselves in our reflection’s shoes!  We are mentally reversing our front-back and left-right, but the mirror reverses only the first.

Think about looking at yourself with a video camera.  Here, left-right and front-back are both reversed (if you’re facing your recording, that is–if you’re looking at yourself from the back then nothing will be reversed).  If you move towards the screen (e.g. north), your recording moves in the opposite direction (e.g. south); if you move to your right (e.g. east), your recording still moves in the opposite direction (e.g. west).  The same goes for text printed on a shirt: in a recording, front-back and left-right are both switched, just like they would be on another person, so the text is legible; but in a reflection, only front and back are switched, so–just like a transparency sheet viewed from the wrong direction–the text appears “backwards”.[2]  To prove that the text on your shirt is not reversed left-to-right in a mirror, you could remove the shirt and point it at a bright light so that you can read it from the inside (in other words, the back–but with the right sleeve still on your right and the left sleeve still on your left).  The text will look just like it does in the mirror: front and back reversed, but left and right the same.

Feeling enlightened?  Confused?  Got a better explanation?  Let me hear it in the comments!


[1] As a child, I once asked my parents how people knew what side of the road to drive on, to keep from crashing.  When they told me “you drive on the right”, I was still confused–“whose right?” I thought.  It took me a while to realize that it didn’t matter–if you’re traveling in the other direction, “right” is on the other side.  This is not an intuitive idea.

[2] If the image I linked is confusing you, think about it this way: the text on the transparency is viewed from the front, so it is perfectly readable.  The mirror “sees” the transparency from the back, so from its perspective the text is reversed front-to-back (just as it would be if you were looking at the other side of the transparency).  But the mirror itself reverses front and back when it reflects the text back to you, so the reflection still appears legible because front and back have been reversed twice.

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Filed under Just for Fun, Science

On Intelligence: A Theory of Thinking

On Intelligence is a book written by Jeff Hawkins[1] on the nature of intelligence, both artificial and natural. It’s an expansion of and answer to an age-old question I’ve referred to before: how do we think? What does it mean to be intelligent? What is consciousness? Might it be possible to create an intelligent machine? And if we could–what would that mean for society? In this essay I’ll attempt to describe his theory, its motivations, and how it can be a powerful and useful tool in any field–even if you’re not very interested in AI.
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Time Travel: What Is It?

It’s common to think of time as though it were a medium one travels through in the same way one travels through space–as in, you can travel one meter through space, or you can travel one second through time. Popular science education reinforces this idea by telling us that time is just another dimension, like the three spatial dimensions of up/down, left/right, and front/back. Yet there seems to be a weird exception in that we can only travel through time in one direction at a constant speed, whereas we can travel through space in any direction and at any speed we like. What if that weren’t the case? What if time’s seeming constancy were simply a technical limitation that someday we could solve? What if we could travel in either direction through time, just as we can now travel through any direction in space? This is the “science fiction” conception of time travel, and although it’s an immensely fun idea that has enjoyed huge popularity for over a century, it rests on a false analogy: time “travel” is a complete misnomer. The seemingly one-way nature of time, and its interconnectedness with space, are foundational to our conception of what it means to “travel” somewhere at all–without them, the term becomes meaningless. Continue reading

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Are We too Harsh on AI?

The search for true AI has been a long, slow, and bumpy one, and the more years pass it seems the slower progress has become. And yet, maybe we are being too harsh on our computers.  We expect our AIs to know everything, to do everything, perfectly, as soon as they are switched on.  Isn’t that a little unfair?  More importantly, isn’t it a little misguided?  In our search for the “perfect solution”, are we actively discouraging approaches that could lead us to machines that are truly intelligent?  Humans, after all, are neither perfect nor omniscient, nor are we born knowing everything.  In fact we are born knowing very little: most of the qualities of human intelligence that make it a desirable thing to replicate–such as language, creativity, and perception–are things we have to learn how to do, not things we are born with.  There is even evidence that such fundamental aspects of perception as object permanence and visual closure must be learned! Continue reading

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