From: chris.m.thomasson.1@gmail.com
On 1/5/2026 3:45 PM, Thomas 'PointedEars' Lahn wrote:
> Chris M. Thomasson wrote:
>> On 1/5/2026 2:49 PM, Thomas 'PointedEars' Lahn wrote:
>>> Chris M. Thomasson wrote:
>>>> On 1/5/2026 1:47 AM, Thomas 'PointedEars' Lahn wrote:
>>>>> You appear to be
>>>>> referring to a definition of "dimension" that is used in science-fiction
>>>>> and fantasy instead.
>>>> [...]
>>>>
>>>> Ponder on it:
>>>>
>>>> (4th Dimension Explained By A High-School Student)
>>>> https://youtu.be/eGguwYPC32I
>>>
>>> The argument that they are making about time (not being "the 4th
dimension")
>>> is pseudo-scientific and ridiculous, based on their ignorance of what it
>>> means when we say "4th dimension" in that regard (which I just explained to
>>> you in detail). Scientifically it is complete nonsense to say "every
>>> dimension has time in it" as they do.
>>>
>>> *Their* ignorance is excusable, though, because they are just a high school
>>> kid and are not expected to know about or understand pseudo-Riemannian
>>> manifolds like spacetime (although they could have certainly have found
>>> books that explained it at their level of understanding). Yours is not (as
>>> I just explained it to you in detail).
>>
>> Say to explain a 3d point in time we need (x, y, z, t), t for time.
>
> First of all, watch this (which was suggested to me by YouTube when I
> watched the video that you referred to):
>
> Dylan J. Dance: Physicist Reacts to 4th Dimension Explained By A High-School
> Student
>
>
> This should clarify (as I already indicated) where that kid was right and
> where they confused themselves and thus were confused.
>
> Then, as to your claim:
>
> Once you specify a fourth coordinate for a point, it is no longer a point
> _of_ (NOT: in) a 3-dimensional space, but a point _of_ (NOT: in) a
> 4-dimensional space. If the extra coordinate is time, then that space is
> (for obvious reasons) called _spacetime_. The point has become an *event*.
>
> In physics we actually prefer to choose the time coordinate as the zeroth
> coordinate (unless we use Euclidean time, as I explained before), and count
> the spatial dimensions beginning with 1. This is more convenient in the
> mathematical formulation and -- since we assume for various reasons that
> there is only one (large) temporal dimension -- makes handling additional
> spatial dimensions -- which according to string theory exist but are "too
> small" to see as they are compactified -- easier to handle. So, as I
> explained before, instead of (x, y, z, t) we write e.g. (x^0, x^1, x^2, x^3)
> := (c t, x, y, z).
>
> We are using "c t" instead of "t" so that the temporal dimension(1) has the
> same dimensions(2) as each spatial dimensions(1); but the "c" is frequently
> dropped in the theory by setting c = 1 (called "notation in natural units"),
> and that is equivalent to not doing that if we specify time in seconds, but
> then lengths in e.g. light-seconds.
>
> (1) "dimension" as understood in mathematics
> (2) "dimension" as understood in physics with regard to quantities
>
>> For a 4d point we need (x, y, z, w, t), t for time.
>
> Again, this is now a point _of_ (NOT: in) a 5-dimensional space.
>
>> t is in every dimension?
>
> No; (different from the sci-fi/fantasy meaning) a dimension is NOT the whole
> of this construct, but merely a part. For example, the x-coordinate of that
> point represents one dimension, the y-coordinate another, and so on. See
> also the video referenced above.
>
Thanks. A bit busy lately. (x, y, z, t) can be dangerous/confusing
because it does not mean a 4d space. but a 3d space with a time tag so
to speak.
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