Philosophy is the study of how the universe is. It's superficially like science, but the methods are wildly different. Science didn't supplant philosophy. Just as philosophy couldn't determine the atomic weight of oxygen, science cannot answer a question like: is morality about actions or their consequences?

Philosophy is a tradition of thought, that originates from a guy in ancient athens. With that, it is a collection of texts.

The topics of these text vary. These text's cover those topics that are usually considered to be philosophical, but also those that bleed into religion, history and science.

Science, or as newton called it: 'natural philosophy' used to be a philosophical discipline. At my university the scientific 'faculty' left the 'philosophical' faculty only in the sixties

philosophy was science in old era in western civilization

I would say rather that there was a split between philosophy and science in the 16th-century scientific revolution. Previously, the role of philosophy (especially natural philosophy, the precursor to science) was to offer meaningful explanations for the universe, using empirical observations to justify the explanations. After the scientific revolution, the role of the new discipline of science was to look for patterns and laws in the universe, whether or not there were meaningful explanations for them. Philosophy took more of a back seat, still looking for meaning in the patterns revealed by science but without steering science in the process.

There are a lot of answers to that question, because there are a lot of different branches of philosophy, and because it evolved over time.

I'd say philosophy is mostly the fact of thinking seriously about any subject. It can be meaning of life, morals, politics, technical objects, science, arts, perception, happiness, etc. Sometimes, when the study of one category of subject starts to be very complex, very distinct, it becomes a field of science in itself : maths, physics, biology can be seen this way, but economy, sociology could be too.

To me the difference experimentation/theoretical is a relatively correct observation, but it is a consequence of something slightly different : sciences are heavily structured, defined systems of thought. They depend on a set of concepts and rules that are accepted and that scientists try to refine. Philosophies are less strictly defined, challenging any commonly admitted concept is typical. So science already has a whole system that facilitates experimentation, while philosophy is questioning its own system and therefore is a bit more theoretical.

Another approach is to see science as "Okay, we have this thing. How does it work ?". Philosophy would be "But what is this thing ? Do we really have it ? Why is it there in the first place ? How can we be sure that we're studying it properly and not missing anything ?".

Thinking about thinking

Philosophy is composed of two root words, philo and soph. Philo means “love of” and soph means “knowledge” or “knowing”. Put them together and at its core philosophy is the love of knowledge.

In ancient Greece philosophers were contrasted with the sophists, those who proclaimed to know things without respecting whether they knew the correct things. As the roots of modern science began to take shape proto-scientists were referred to as natural philosophers with a love for knowing about the natural world. When universities began offering doctorates, they were named to have a doctorate in philosophy of (phd) their subject to declare a recipient had shown a love of knowledge in their field of study.

If you are trying to learn for the love of the game, you are practicing philosophy. Any attempt to add onto that I can think of just dilutes that or starts breaking to into different fields within philosophy as a whole.

Indeed... 🤔