At approximately 300 degrees Celsius, water cannot be liquidized unless pressure is applied, but this only works if the temperature is below its critical temperature of 374 degrees Celsius. Above this critical point, water exists as a supercritical fluid, which is neither a liquid nor a gas. The discussion highlights the confusion surrounding scientific terminology, particularly regarding phase transitions. It's clarified that while water can remain a liquid at temperatures above 300 degrees Celsius, it must be under sufficient pressure to do so. Understanding these concepts is essential for accurate discussions about water's state at high temperatures.