It came to me all of a sudden that I was unable to define scientifically the concepts of distance and time, without of course in turn using a parameter which is a consequence of these two concepts, velocity. So somehow it comes in a whole loop back on itself, which is frustrating.

 

Sure, we say that time is "how long" it takes, but I find that a rather unacceptable definition scientifically. Distance is how many ruler lengths something is, which is again not precise with all the things such as general relativity and other theories out there that totally mess up intuitive definitions.

 

Any ideas? Though I think this may turn out to be a stupid question, but I thought I'd give it a try.

distance: The space between two points

 

time: period spent travelling along the 4th dimension

 

any better?

It's not you. All definitions are, at some point, circularly dependent.