Asklemmy

Marxism-Leninism is an ideological framework. Essentially, it fronts dialectical materialism, the materialist conception of history, and Marxist political economy as correct. There is no one "Marxist-Leninist form of governance," just as in real life there is no one universally correct form of governance. However, all of the component parts of Marxism-Leninism are correct, including dialectical materialism, which is the basis of correct scientific analysis and interpretation. It is not a replacement for the scientific method, but a way we understand the world.

What you describe is broadly empiricism. The limits of pure empiricism are that, if we are being truly pure, we do not draw connections between linked phenomena. In other words, we do not assume gravity will be the same tomorrow as it is today, because we have not yet tested it. As the world is constantly changing on both a micro and macro scale, this means each test is in fact fresh, with fresh conditions. Empiricism, taken to the extreme, denies this understanding.

Dialectical materialism expands upon empiricism by recognizing the interconnection of everything, and that knowledge is something continuous. As we test the world, we gain a better understanding of it, and therefore the world is always changing so our knowledge is always becoming outdated as long as we are not continuously testing and practicing. Through practice, we gain better knowledge, with which we can better predict what will happen.

There's nothing spiritual about Marxism-Leninism. Knowledge comes from practice, of course it does. However, without acknowledging that we all have a world outlook, this solidifies what might be incorrect, such as idealism or metaphysics, as has often happened in the field of science.