Just a quick FYI, A Level is a big step up from GCSE's. So Business studies in A Level would tend to be a lot harder than GCSE's in all aspects of learning such as memorizing and essay structure and planning.
However, Economics in A Levels is a lot harder than Business A Levels. It is said that Business is considered more as a 'softer' subject whereas Economics is more intellectually stimulating. And I know this question is related to the difference between Economics and Philosophy but I thought this this level of information was worth mentioning as it seems you have quite a lot doubts when it comes to the difficulty of Economics.
I personally haven't taken Philosophy as an A Level (although I may have considered it as its a really interesting subject). However, I did take Economics. Economics is MUCH more than just memorizing. When I took Economics, I really wanted to do well and aim for top grades but I had to put ALOT of effort in it (sometimes more than other subjects). Economics requires you to learn about real world situations and you are expected to apply information to businesses, political issues, economic arguments and even mentioning popular theories by past Economists also awards marks. This requires ALOT OF RESEARCH; not just class work but a lot of your outside studying. In economics there is also a considerable amount of Mathematics involved for a social science. Its usually just GCSE level Maths of course but still essential. There is obviously certain things you have to memorize such as key words and understanding concepts in each topic and subtopic is also essential. However, stating what a textbook says isn't the purpose of the Economics A Level but more to do with your reasoning and thought process when making intellectual arguments that they may throw at you - while also providing evidence for your arguments too.
You can judge how hard Economics is for you. For some its easier than others. But in my opinion, Economics is a great A Level and I don't regret doing it one bit. Arguably the most interesting subject I took.