In 1739-40 the English Philosopher David Hume published the book ‘An Enquiry concerning Human Understanding’. In it he outlined the problem of inductive reasoning.
Inductive reasoning is making a series of observations and from these, coming up with a claim that links the observations. For example if the gardener of next door comes on Wednesday afternoon for a number of weeks, we would infer he will come the next Wednesday. We see a pattern emerging, allowing us to make a general statement about the nature of things.
Another example is the sun rising each day. It has risen everyday since we were born, so we expect it to rise the next day. But we cannot actually say for sure that it will rise the next day. We have a strong belief about what will happen based on our knowledge of planetary dynamics and past experience, but we cannot say for certain it will.
Deductive reasoning on the other hand leads to definite statements about the result. This reasoning is used in mathematics to create proofs. We have a set of axioms, e.g. a triangle has three sides, and from these draw conclusions about the mathematic world. The reason we know we won't wake one morning and find the pythagorean theorem doesn't work, is that mathematics is self contained. There are no inferences made within mathematics. Everything is built from some sort of definition.
Science on the other hand is built using inductive reasoning. Deductive reasoning is used within science but they are built from inductive premises. For example we can make some observations and see the mass of objects do not affect how fast they fall to the ground. If we drop a bowling ball and a tennis ball at the same height, they reach the ground at the same point. We can go on to use this in deductive reasoning and develop a theory around the observations, but it is only as good as the truth of the observations.
What started out as a hypothesis, now becomes a theory through repeated experiment. It hasn't been proved true, it just hasn't been proved wrong. Yet. It is a working statement about the universe. On the throne ready to be overthrown. Science is not absolutely sure of anything, it works on approximate answers and uncertainty.
David Hume outlined that what we see as casual relations cannot be justified based on inductive reasoning. For example if we go to roll a ball down a hill, we can only say what will happen based on past events. But the only reason to believe inductive reasoning is that it has worked in the past. The evidence for inductive reasoning is itself inductive reasoning.
Where do our thoughts fit into this? When we have a belief about ourselves or a possible outcome, we are using inductive reasoning. But how many stringent scientific experiments have we run to come to the belief in our head? Not many. Our mind has seen how past events have played out, and has come to some general statements that it can act on to interact with the world efficiently (or inefficiently!). For example our beliefs about money, who we are as a person, who family and friends are. But they are just beliefs.
When we meet someone who has a lot of emotional baggage, they are bringing a lot of beliefs about themselves and the world along with them. But who's to say that these beliefs will hold true in the future?
Are they true at all?
When we have an emotion or feeling, its precursor is usually a thought. Its not reality making us feel in a particular way, its how we interpret reality based on our beliefs that is making us have the feeling.
For example, if you got a phone call and your neighbour said
"Your house has be robbed and the windows are smashed."
We may feel anger, sadness etc. But then he says "Just joking!".
We would suddenly feel relived (then possibly angry at our neighbour!). It wasn't the event in reality that caused your feelings, it was your thoughts about the event that brought up the feelings. We believe we shouldn't be broken into, or I'm cursed that this always seems to happen to me, or somehow this reflects badly on who I am.
The beliefs we have aren't mathematical proofs, held true for eternity. They're generalised statements about how we interpreted our past.
Hume's analysis of inductive reasoning applies just as much to our thoughts and beliefs. There is no reason why we should expect that past observations should bear any truth on future events. Like theories in science, they are there as approximate theories ready to be proved false.
But unlike theories of science, our phycological thoughts and beliefs don't have rigid physical reality to support them.
The only way they keep being true is that we believe they are true. When we stop believing in them they stop being true.
We can choose to not believe a thought. If our mind tells us we aren't living up to our potential. This is a thought within our current perspective and societal influences. But we don't have to believe or take to heart thoughts that arise. We don't have to get caught up in them, and think they are us. The story we tell ourselves is just thoughts.
When we are able to step back from our thoughts they no longer have the same emotional impact they once did. We no longer feel anxious or depressed over a thought that arises. There is no longer a good or bad outcome, a right or wrong.
There is just awareness.