Well technically, you can merit yourself if you have two (2) accounts that have merits to send on. But if you do not have any alternate accounts, then meriting yourself is impossible in any way.
I believe @OP is talking about an account to merit itself and not by other account owned by the same user. So technically speaking, the answer will be always a no.
That's funny, because that's what I asked myself 5 years ago or so. In principle you can click on the merit tab and even try to merit yourself, the only thing I preferred to ask at the time rather than merit myself because it could have been seen badly by the community even if it was an experiment if it worked and I got to send a merit to myself..
If you are that curious and wanted to not be the subject of flame, then you can just create a thread on Meta explaining the topic you wanted to explore yourself before trying to check if self-merit is allowed by the forum system. You can even publish the step by step procedure or make a video of it. This way you can establish a proof that you are not maliciously intending to use a possible exploit but instead you are just exploring stuff for self-awareness.