# cogito ergo sum

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Posted by: stak
Posted on: 2006-12-10 10:53:58

there's been a spate of articles recently that have gotten me thinking about assumptions again. more specifically, the assumptions we make everyday and which we build our life on, but that may or may not be true. assumptions like these are all over the place, and every once in a while they get revoked, making us realize how we've been doing things wrong for so long. i thought it would be an interesting experiment to try to formulate a set of facts that are based on no assumptions (or as few assumptions as possible, which would have to be explicitly stated). kind of like the Principia Mathematica, but for general truth, rather than math. so, here goes..

1. I think, therefore I am. i'm pretty sure descartes was right on this one. i'm thinking right now, so there must be some sort of entity doing that thinking, even if the entity is just a thought. define "I" to be that entity. also, define "universe" to be the set of all existing entities. since the universe contains "I", we know it is non-empty.
2. My thoughts are changing, so the universe is not static. i think different things. even if all these thoughts happen to co-exist in the universe, there must be some sort of "pointer" to the active thought, which is moving from thought to thought. or it could be that one thought is being replaced by another. either way, there is some sort of change happening, so the universe is not static. Note that this does not imply that I am changing, only that the universe is changing, since it could be some other thing in the universe combined with myself which gives the change.
3. Time exists. change is nothing but variability over time. therefore, if change exists, some concept of time must exist. time is therefore the first dimension of the universe.

that's as far as i've gotten. i think change might also imply the existence of "moving parts" in the universe, and therefore at least one other dimension, but i'm not fully convinced of that yet.

of course, this entire exercise might be moot, since i'm not using formal logic in my deductions, but i'm not sure of how to express this stuff in formal logic. it should be possible with the appropriate definitions, since formal logic systems are sound and complete. oh, and either way, there's some sort of assumption here that logic is not flawed and can, in fact, give you more facts from pre-existing facts.

 Posted by rohan at 2006-12-11 00:48:28 I don't agree with 2 (and be extension 3). What if all your thoughts exist at the same time, and each thought "thinks" that it is the current thought? At any instant, if your thought has just changed, you have no way of knowing whether it actually changed, or whether you are permanently in a state of believing that your thought just changed as it did. For example, have you ever noticed the following: you look towards a clock with seconds, and the second hand/number appears momentarily frozen for longer than one actual second before it changes. That's because your brain overwrites the near past with a memory of having been looking at the clock for longer than you actually were. (This has been more rigorously studied by psychologists I believe, so I'm not completely making this up). So you never really know if what you think is a past state actually happened or if it's your present state inventing a fictitiously different past state.
 Posted by Lin at 2006-12-12 12:11:43 I am not sure I buy the argument that all my thoughts exist at the same time. The mere idea of it existing means that I am devoting a part of my brain to it. The thoughts change as we change, as we adapt to different experiences. Does the brain have infinite resources to provide for all situations? :D
 Posted by stak at 2006-12-12 22:34:54 Well, given we're starting from scratch, sure, why limit the brain's resources? But more importantly, all your thoughts aren't existing at the same time. It's just that at any given time, all you have is a current thought and memories. You don't actually *know* that your thoughts are changing because you can't rely on your memory. The memory may be static too. Another way of looking at it is this: imagine that the universe just froze for 5 minutes. Everything, all the molecules and atoms and quantum thingies, just stopped moving completely for 5 minutes. After everything resumes, is there any way to tell that it was frozen? Everything you would rely on to tell you would also have frozen, so there's absolutely no way to tell. The same thing applies, except it's like a freeze for an infinite period of time.
 Posted by stak at 2006-12-24 20:43:27 Hm.. true. Well, there goes that. How about we make an assumption that the universe is not static, because if it is, well, that's kind of boring.
 Posted by rohan at 2006-12-11 23:43:45 yes, you can't do much without assuming that.