Trading without indicators is still possible. It's just that, the final result of trading without indicator will not be same as trading using indicators.
Without using indicators, traders do not have a specific benchmark in making decisions. Open or close positions are only done randomly and in the end this can lead to losses in trading. There are cases where trading without indicators can make a profit. But this profit will not be consistent, even though consistency of profit in every trade made is very important. Not only that, trading without using indicator analysis will lead to a game of guesswork or even worse, to gambling.