Understanding the Fourth Dimension: Time in a 4D World

Can we say that we live in a 4D world if we consider time as the fourth dimension? The answer is yes, and this thought experiment with rolling a dice will help illustrate the concept.

Experimenting with the Fourth Dimension

Roll a dice. If you are successful, this experiment proves that there are at least three spatial dimensions and one time dimension. While it does not definitively prove that there cannot be four or more spatial dimensions, current physics models generally rule out the presence of additional spatial dimensions.

Conventional Modeling of Reality

The four-dimensional (4D) concept is not a mystery. It is a conventional way of modeling reality. The first three dimensions are length, width, and depth, or the three location coordinates as defined by Descartes. The fourth dimension is time, because any event occurs not only in space but also within the ongoing processes of the movements of everything in reality.

For example, if you want to meet a friend for lunch, you need to specify their location in three dimensions (length, width, and depth) but also the time (e.g., 1pm on Thursday). While time is a commonly used term in everyday language, from a strict realism perspective, it is merely a way of codifying the ongoing motions and processes we observe around us.

The Mathematical and Physical Perspective

The question of whether we live in a 4D world requires understanding the mathematical spacetime coordinate system. Time is one of the dimensions in this system, alongside the three spatial dimensions. Studying spacetime physics and its mathematics can provide a clearer understanding of this concept.

In physics, a dimension is understood as a measurement. Objects do not move in dimensions; they move within what we call "space." However, space itself is a conceptual framework, not a physical entity with mass or volume. If you are looking for a strictly material context for motion, you can say that objects move through fields because fields like the gravitational, magnetic, and electrical fields are physically real and tangible.

An object cannot move through a dimension in the same way it cannot walk through a number. A dimension is a quantity, a metric, which can be used in mathematical equations to make accurate predictions. Time is a measurement that represents the rate and duration of an observed action. It is important to note that when we discuss time, we are often referring to it as an abstract concept. This abstract concept has been deliberately conflated with the fourth dimension in popular culture and fiction, which has led to much confusion.

Conclusion

At its core, a four-dimensional model includes all physical objects having spatial dimensions (length, width, and depth) and all being in motion in various ways. We model all of this with four measurements: three spatial and one temporal. This perspective is rooted in the principles of spacetime physics, where time is as crucial a measure as the three spatial dimensions are.

The key takeaway is that while the concept of a 4D world, with time as the fourth dimension, is a fundamental part of our current understanding of the universe, it is a conceptual framework rather than a physical reality. Understanding this framework through the lens of mathematical and physical theories can help demystify the fourth dimension and provide a clearer view of our world.