I have to admit that of the four kinds of slavery that prevent us from thinking well and thinking for ourselves, slavery to custom is absolutely my favorite. The problem is that 75% of everything we say is said because of custom and not because we have thought out the truth for ourselves. (DISCLAIMER: I have not actually verified this percentage through the customary “scientific” study- so I am willing to admit that the percentage is much higher- say 90%)

If nothing else Descartes was very sensitive to the ideas which he held through the force of custom when he said in his first meditation,

For those old and customary opinions perpetually recur– long and familiar usage giving them the right of occupying my mind, even almost against my will, and subduing my belief.

Apparently it was his keen awareness of this fact – that his mind was full of thoughts held through custom and not through reason- that led him to perform the remarkable feat which I refer to as the “catastrophic Cartesian Brain Dump”

this is what he is talking about when he opens his unholy Meditations by saying

“SEVERAL years have now elapsed since I first became aware that I had accepted, even from my youth, many false opinions for true, and that consequently what I afterward based on such principles was highly doubtful; and from that time I was convinced of the necessity of undertaking once in my life to rid myself of all the opinions I had adopted, and of commencing anew the work of building from the foundation…

and then he proceeds to throw the baby out with the bathwater!

it will be sufficient to justify the rejection of the whole if I shall find in each some ground for doubt.

And he proceeds to enunciate his doctrine of universal doubt or what we now embrace in our day as an intellectual virtue called ‘critical thinking.’

Rather than following Descartes’ (Descartes’s?) example, let us make the attempt to sift through our own ideas with a fine toothed comb to discover the things that we think merely because of custom rather than through reason. We might add that there is such a thing as right custom. Not all custom is bad. Nonetheless- wherever possible it would be nice to begin to know ‘what we ‘know’ and distinguish that from ‘what we don’t know.’

Perhaps one way to begin this sifting process is to make an attempt to distinguish the various kinds of custom. How many kinds of custom are there? I can think of at least three.