Logical positivism
The logical positivists tried to say that everything valuable was scientific and vice versa, and had a metric for judging ideas based on seeing whether it is logically consistent. Even physics is not logically consistent, so the approach was doomed from the beginning. Karl Popper (1902–1994) dissected it in detail, and Quine delivered the final blow with his 1951 paper. Still, even today people on the Internet sometimes reinvent logical positivism, so it helps to know the history.
The field gradually transitioned into "linguistic philosophy" which lived until about 1970 before falling out of favor too.
Linguistic philosophy was the attempt to say that philosophy's area of focus was just the interpretation of words. It's a very narrow interpretation, and many would say, hardly philosophy. But it was a thing particularly in Oxford. It appealed to them because they could reckon that everything not expressible in language was not worth considering, which if true, really simplifies life.