Several principles in physics lead me to deduce that mass is a temporal phenomena.
1) A point particle mass, or the center of mass of any object, has no spatial extension;
2) Mass affects time dilation;
3) Acceleration affects time dilation and acceleration is a second order time derivative;
4) "Dark matter", which is invisible, undetected and collision-less, affects the rotation curves of galaxies, where rotation is time dependent phenomena;
5) The more massive an object, the more energy/work it takes to move it, where the total work along some path is similar to time integral of calculus;
6) If all of these mentioned physical phenomena (and others) correspond with mass and time, and spatial extension is not necessary for mass or for time, then it is reasonable to formulate a temporal definition of mass.
The Wince vs Susskind video series shows how I get from the basic Existics equations to defining mass as either a negative volume of time or a negative temporal scalar. How I actually arrived at "mass emerging from the 4 T metric" is presented and has to do with the success of the 4-vector model as apposed to introducing a 6-vector model. The 6-vector (3-time and 3-space) doesn't work very well. However, since the traditional 4-vector does work, I can formulate a temporal 4-vector and either bring "t" into the traditional 4-vector as a vector or I can bring "s" in the temporal 4-vector as a vector. By doing this, the negative passage-of-time reveals what time dilation is and how both mass and acceleration dilate time.
Based on your other two questions, it seems you "get it" for the most part. The more you ask me pointed questions, the more I am able to clarify my line of thinking :)