Earlier quoted context omitted.
>Utility is a well-known concept in economics. It's well known but it still has a circular definition. Why do people spend $X on goods? Because it provides $X worth of utility. Why does it provide $X worth of utility? Because they spent $X on it. Ultimately it therefore ends up being rather meaningless. It's also non-disprovable which makes it non-scientific.
It's not meant to be scientific. It's a tool for abstracting a situation down to understand the intent rather than the details. Your first mistake here is to try and assign a '$X worth of utility' - utility is not a unit which can be expressed in another unit. Someone can spend $x on something which gives them utility, but equally they can go for a hike in the mountains which provides greater utility to that individu…
Neoclassical economics definitely does make a pretense of being scientific. As does Marxism.