Three laws often paraphrased as:

1. You Can't Win
2. You Can't Break Even
3. You Have to Play

Actually, those are the three Laws of Lost Wages, or Las Vegas for short.

Around 1840, Rudolf Julius Emanuel Clausius is most often credited as author of the first Two Laws, although several people published related works in thermodynamics. Sadi Carnot’s work in the preceding decades provided a basis for proving all three Laws, but never expressly declared them. Sadi states a belief that amounts to the First Law, that energy is never lost, only moved around. Carnot worked within the scientific consensus of the day, heat is an "imponderable material" flowing through all matter, which led to his waterfall/fluid model of heat. (He did express doubts). Despite using a flawed model, he proves up enough facts about thermodynamics to formulate all the laws authored by later scientists. Sadi Carnot is properly credited with being the father of modern heat engines and their theory, and provided the foundation for the entire study of thermodynamics.

For the era he worked in Carnot's precision of measurements was astounding. For example, he notes that at very low temperatures, gas pressure diverges from gas temperature. This is the opposite of what we now use as the Ideal Gas Law, which in in effect says pressure is a direct multiple of temperature. Carnot's measurements were not wrong. In his era (and all over his and Lord Kelvin's paper), -267 is used as the number for absolute zero. The modern value (Kelvin scale) absolute 0 starts at -273.15 degrees C. So Carnot's measurements were right, the contemporary 1820's value of absolute zero was wrong. Using the modern value (Later set by Lord Kelvin), the same measurements would show no divergence of gas pressure vs low temperatures.

So back the the laws of thermodynamics. The First Law, Conservation of Energy, or "the one that matters", is that Energy is a constant. For thermodynamics, Energy = Heat + Work. Energy is not created, lost or destroyed. This fact allows for designs approaching 100% fuel efficiency. (More to come.)

The Second Law of Thermodynamics is often misquoted as "proving" it is impossible to completely convert heat into work. Various forms of the law all amount to (paraphrased) it is impossible to completely convert heat to work unless something else changes with it. In fact ALL heat engines depend on "Something Else Changing." The "something else also changes" is almost universally left off all the various restatements of the second law, which wouldn’t be so bad were it not the point of the Second Law.

The important thing, is that it was finally recognized that heat IS actually consumed when converting it to work. There is no "fallen" or "used up" heat left to pour out to make work. In fact pouring out heat cannot create work. That is simply impossible. Pouring out heat wastes energy. Pouring out energy (heat or vapor or work) is the ONLY way engines can be inefficient.

Three laws of practical thermodynamics can accurately be paraphrased as:

1. You Can't Win
2. You Can't Lose
3. Unless You Do Something Silly