I hate when people state that time is the 4th dimension. It quite clearly isn't.
Imagine a 2D environment, is there a nil third dimension so that time may still be the fourth? No! Time is the third dimension there. Generalise to any n-dimensional space and find that time appears to be dimension n+1.
But how can time consistently be dimension n+1 for any n-dimensional space? Answer: It isn't! It's quite simply not a dimension. (Try going back in time as you would along a path.) Time is a ``window'', if you will, to observing the n+1th dimension!
To illustrate: Imagine a 0-dimensional dot. It flashes white, black, white, black, changing colour once a second. Within its 0D space, it is just a flashing dot, but visualise it moving along a path and bam - you're tracing out a dashed line in 1D!
Similarly, start up a first person shooter and stand still. It's a 2D static image of a scene, right? Now move your character forwards. Suddenly, the scene comes to life, and you appear to be moving through 3D space! Without movement as a function over time, you would not ever see the scene in 3D. (Not you personally, as humans are predisposed to seeing things as/in 3D. But I hope you understand my point.)
I postulate that most people see time as the 4th dimension itself, simply because they have not the capacity to imagine space with four dimensions, much like an inhabitant of the 0D world not being able to grasp that the flashing could ever trace out a dashed line in a dimension they have never experienced.