Look at what is actually going on and not what thoughts say - but what actually is.
1. What is memory exactly?
A store of THOUGHTS “about” events, things, thoughts, etc.
2. What is the memory ‘made of’?
Thoughts, images.
3. WHEN does the memory appear?
When we think, every time we think.
4. What is the exact difference between a ‘general’ thought and a ‘memory’ thought?
No qualitative difference. Let’s take these two sentences as examples,
a. “Freedom is important” (General Thought).
b. Now I “remember” myself thinking about freedom yesterday (Memory Thought).
Both sentences are “conceptual” in regards to the present moment, and both have no physical basis or reality in the moment.
5. How is it known EXACTLY that a ‘memory’ thought refers to something that has happened?
We just have a strong “feeling” about it, we can be sure only if we check some archives etc.
6. Then, look at a thought about the future.
What is the future thought ‘made of’?
Thoughts, images.
7. WHEN does the future thought appear?
Here now.
8. What is the exact difference between a ‘general’ thought and a ‘future’ thought?
No qualitative difference in the sense that both are "non-actual" in the moment.
9. How is it known EXACTLY that a ‘future’ thought refers to something that will happen?
“I will have a meal with my friends tomorrow.”
This sentence “gramatically” refers to a potential for tomorrow. The content might turn true or not, that cannot be known certainly now.
10. Then let’s compare a thought about past and a thought about the future.
What is the EXACT difference between the thoughts about past and future?
No difference except their “themes” (“past” and “future”). They are both thoughts, both are conceptual, and both are "non-factual" (non-physical, imaginary) in the moment.
11. If there is difference and how is that difference is known exactly?
No qualitative difference.