About the topic
I believe the right answer is to admit that answering this question is impossible.
The question itself is irrelevant, too, if you think about it: your choices, free or not, lead you in a certain direction. In the end the only thing we can attest is that we made choices, were it free or not. Now if the whole life was planned, the thing, nature, evolution or god, that put this planification for a particular purpose may very well have put a set of strong mechanisms to master the output the controlled system (me) gives from any set of choices.
Freedom or
illusion of freedom.
The consciousness I have of my world, the spatial sum of all the electric patterns running around in my brain at time t, is not the same pattern as the consciousness YOU would have of it, were you put at the same spot of observation. Given the same base toolset (human brain according to human DNA), your past experience favored a set of synaptic connections at the expense of others. The throughput of the digital feedback loop that would modelize your intelligence is not the same for ME, than for YOU. I would and cannot thereby make the same choices than you would at the same point. From there on, if these choices are illusion of freewill, then they are part of a bigger plan, and if this is the case, we cannot even state it since its explanation transcends our own level of comprehension. We ARE comprehensively limited. Modelize in your mind a 0 dimensional space: it's a point. 1 dimensional space: it's a line. 2 dimensional space: it's a plane. 3 dimensional space: it's a sphere. 4 dimensional space: it's a sphere moving with time. now, 5 dimensional space anyone ? Here is our limit of comprehension.
Always keep in mind that the part of our consciousness of which we are in control is shockingly small. The one or two dreams we remember in the morning hide the 30 or 40 ones we had that vanished away. Another explanation of déjà vus meets the explanation we can make of trance phenomenons by mystics and gurus of various religions. Resonance. Intelligence is a loop in the form: I
sense how things are - I
think about what they should be - I
act upon them, AS LONG as I don't sense them as what they should be. This is a behaviour very similar to analog feedback loops in electronics or digital filter algorithmics. Imagine a satellite TV receiver parabola, that needs to be perfectly lined up with the satellite in the sky. When you install the device, you enter the coordinates and a little rotor is put to action to rotate the device towards the desired direction. As long as the device
senses that half the remaining angle hasn't been covered, the rotor
accelerates. Then, coming closer, it decelerates and stops. Now what happen if you change the target WHILE the rotor is already in movement towards another target ? You get a fuzzy tracking behaviour which is just comparable to the aiming algorithm we have in our bots. The resonance phenomenon is, in these devices, the offset between two distinctive targets that make the loop or the algorithm go berserk if you alternate targets successfully for a long period of time. Just as sometimes, very rarely, it occurs that you see one bot trying to aim alternatively at 2 distinctive enemies, locks on one, skips to the other, comes back to the first one, tries to lock on the second and so forth. Within a few seconds you can see the bot's aim going more and more frantic, less and less accurate, and finally go completely berserk and jiggle around everywhere but on the target. The same thing can happen to analog devices (such as satellite receivers in the example above) if you keep entering contradictory targets in bursts. In our former example the receiver's parabola will start spinning around like crazy until someone unplugs it.
This is called the resonance phenomenon.
Being a feedback loop too, the same thing can happen to intelligence. It mostly happens in dreams where the sinusoidal alpha waves of the brain get in sync and start waving all together on very large amplitudes. But it also happens to awaken people - we then call them mystics, or gurus. The amount of thoughts processed in such a state of mind is unquantifiable, but most certainly bigger than huge, and chances are that your déjà vu fits there.
Another explanation is the encoding in which our memories are preserved. When I see a face, I don't remember a
face, I remember the minimal amount of information my brain needs to rebuild this face out of my memory. When I hear a noise, I don't remember a
noise, I remember the differences in the synaptic connections that were active in my brain that made it identify this event as a "noise". When I taste something, I don't remember the actual
taste, I remember the
feelings associated with it (which is nothing more than electric patterns conveyed by different means, from nerves to pheromonas - but in the end they all end up as
electric patterns in your brain). The encoding of the memories, what people (and especially women) like to call
feelings, is just that pattern-based. And the characteristic of a pattern is that it can fit in several situations. The more complex the pattern, the more accurate it is, and the less situations it applies too. But the more simple the pattern, the broader set of situations it applies to. The proof of this is when one feeling recalls you another. It occurs often by children - that one emotion reminds you of a completely different one. That, for example, one color reminds you of the
voice of your mother. Or that one sound feels
warm. Or that one temperature feels
acid (we say: frost "bites"). These are simple patterns of which we see they do apply in different situations.
Stefan's dentist has been formed through such a pattern that may (or a quite similar one) have been invoked by his brain in a cognitive or non-cognitive event formerly, for a totally different purpose.
This topic is interesting