In Calculus, a linear function is a function that, when graphed, appears as a straight line.

Opposite of this, the entirety of Calculus has built upon an assumed understanding of time, where an objects position at time $t$, is given by $f(t)$, and it's velocity is $\frac {dx}{dt}$, the derivative of $f(t)$ with respect to time, and the acceleration is the second derivative.

The fundamental concepts of the two sectors of Calculus are limits: the derivative of Differential Calculus is a limit, as is the integral featured in Integral Calculus.

Calculus

If we're treating time as something continuous, and we index $t$ to the Real numbers, then we are forced apply the concept of limits, from Calculus, to the value of time, meaning it will get arbitrarily close to, but never quite reach the lower bound of $0$, or the upper bound of $\infty$.

The issue here, is that these arguments, descend from a time when science and religious beliefs were intimately linked, within the work of these scientists. Newton, the creator of Newtonian, or Classical Mechanics, believed his observations to be influenced by God. This is also the individual who, alongside Gottfried Leibnitz invented Calculus. Leibniz in fact, believed that the earth is the pinnacle of creation.

Calculus