And, for this reason, then, Einstein felt that all the circumstances must be reported, and not just what it is you happen to find on your scales there as you weighed the phenomena, what went on within the test tube. This brought about Bridgeman's feeling that there should be a name for the inclusion of the unique circumstances under which the observations are made, and he then gave the name "operational" which he used to differentiate from a school of philosophy that was then had been in operation, coming from a man named Pierce at Harvard, called the school of pragmatism. In other words, it was pragmatic, but he wanted to use another word than pragmatic, so he used "operational."

Since that time the word "operation" has come into very popular use in military ways and everything else coming from scientists, but that is where the word began.

I am, in my geometry explorations, as you see me getting into structures and so forth, discovering that the process of thinking produced a geometry. It was just the process of thinking about our experiences, and that our experiences were omni-directional, so when we divide the experiences into all the ones outside and all the ones inside it created a geometry. It just automatically produced a polyhedronal, some kind of definition of what produced the insideness and outsideness. So a geometry has been developed by being very careful to remember, at the outset, everything really I can. What I personally was conscious of in doing when I was participating in what I called, what we call, thinking. And there are many other things I am sure that went on that I am not conscious of, but the point was that these were the things I was conscious of and they lead to a great many clues. So that's all "operational" procedure. So all of my geometrical exploration from there on, is what I call really it's all OPERATIONAL MATHEMATICS. I have absolutely no axioms. There is nothing that is said to be obvious. Where our eyes are too superficial, we now know how small the spectrum electro-magnetic range of frequencies you and I can tune in, so we just cannot see adequately to say, "that is self-evident."

Now, I find that mathematics can play games, assuming certain conditions to obtain, which I will not play. Now, I am an "operational," and I often like to use the word "experiential." I find that experiences can be inadvertent, they happen to us, and then there are the experiences which are deliberate. So I call one, it is "experiential" when it is happening to us, and I make it "experimental" when we set up when we manipulate the conditions arbitrarily.

Now, in my carrying on with you, doing what I am doing on this particular occasion, I am almost 80, within a few months of 80 now, and I am operating completely extemporaneously. I do not have any notes, and I have made up my mind to, because we have tried on several occasions before at various schools around the country quite a number of years ago, where I was asked to exhaust my thinking, my spontaneous thinking before a class of students; and where I would not repeat myself, except to do important reviews to bring back in a strand of thought, which I had introduced later that needed, that you had to be conscious of tying it in. And, I was asked to exhaust my thinking, all the thinking which both the class and myself agreed, was not in the general way of thinking where I had any sort of unique viewpoint as a consequence of my operational procedure in developing my thoughts and self-discipline.

In the previous experiments we have made we had one that came to 52 hours, and because I am older though I may be able to condense things a little more, I probably we are all having such an acceleration of experiences, as I opened with you last night the input of information is so great, that I probably will take a little longer now than I did before, so we made an allowance of about 60 hours. But I also arranged my affairs in such a way that I will have the least possible intrusion into this pattern while I'm doing this, so that I will be able to really remember from day to day everything I've said over the total 60 hours. So I'm going to be really working on, I'm working on a mental tapestry, and I am introducing thoughts, and so forth, and I am bringing in threads and you'll find me continually weaving. But working on the grand strategy I introduced to you yesterday working from the whole to the particular. It is a synergetic strategy; and requiring, then, statements of the whole and some of the known inputs, and finding out other things as we go. This is the grand strategy.

So, that's enough for an "operational" statement about what you find me sitting up here doing, and because this is a very unprecedented affair, unprecedented affair is just to have this beautiful video tape. I don't know if you've been looking at the quality of the picture. It is really superb! And on video tape you're able to do what you do is just tape like tape recording a voice, you can run it over again. We can come back again later on where I've been talking about some object that we don't have models of, or pictures handy, and we can superimpose it back in the film at the right place. It is a very beautiful and lovely medium. And, so we are getting then a really very faithful recording of a completely live experience of you and I. I HAD TO HAVE FACES BEFORE ME. HUMAN BEINGS BEFORE ME, SO THAT I COULD REALLY FEEL THEIR EYES, AND I COULD NOT HAVE PEOPLE WHO CAME IN AND OUT. If someone new appeared in the audience, I would then spontaneously want to bring him up to date with what the rest of us were thinking, so that we've had to have fairly clear-cut plans of how we would carry on here. I think all of this is important to have in the picture because that's operational information. In other words, personally, I do not look upon our undertaking as from somebody trying to create a beautiful moving picture. Where they are just interested in the photogenics or whatever it may be, and certain dramatic moments, and getting the audience to feel in certain ways. Therefore, I do not go by protocol or anything to try to erase anything that seems to be any kind of a form-marring item. I think all of those things are going to be very important, operationally, in whatever goes on here. This is we are all dealing in that extraordinary phenomena called "reality."

Now, today I'm going to do some more reviewing of things in fairly large ways. There is something that is very much in evidence in the room here, and I have not talked about, and it relates to our word "structure" of yesterday. And that is, you see models around here which are these compression members do not touch each other, and if you try them, you'll find that these are flexible cables between them. They are not stiff little wires, and they are not rods they are literally completely flexible threads. And they are high tensile threads Dacron so they will not stretch. But we see then, a complex of compression struts that do not touch each other, and the only thing that is continuous is the tension.

Now, I became very fascinated in my early days of getting into structures and actually building things, and particularly dealing with boats and the very great strength of the rigging and strength of your ship compared to the kind strength that is usually exhibited in houses.

And the differentiating of the rigging of a ship into the compressional spars and the tensional cables and stays, halyards, all the things you operate a ship with. So, I'd like to think a little about any structural system. We introduced those words yesterday, so now you know what I'm talking about there, and we find that in the structural system is a complex of energy events which interacted with one another produce a stable pattern; but some of them were trying to explode and some of them were trying to come together escape the system, and others were containing the system.

And, I find then, this phenomena, compression and tension, that is always and only co-existent. I think lots of people say, I have just a compression member. Well, their compression member is a high tide of a compressional aspect. But it does have radial tension in it, and we say I have a pure tension member, that's not so. You'll find that tension is also co-existent with compression. And to make that clear to you, I'm going to then point out to you for instance, I take a piece of rope, It's very flexible, and the only way that it can give you any dimensional positioning stability would be when you have it tensed. So we take this piece of rope in our two hands and start tensing it. And the tighter I pull it, the more vigorously I pull it, the tauter the rope becomes. When we say "taut," we mean, it's girth begins to contract. That's so as a consequence of my tensing it in this direction pulling on it this way. It is contracting this way that is, it's girth is getting less it's getting harder, you'll find it tighter and tighter. That is, the more I pull it, the more it goes into compression in a plane at 90 degrees from where I'm pulling. That sounds familiar to you from yesterday that's precession. The effects of the pulling, the result is 90 degrees.

I find that when I take a number of rods steel rods, and I found that they are very flexible if I push it this way they want to bend. I'm going to take a bundle of steel rods an eighth of an inch in diameter. They are four feet long, so that they are so long that they are very slender, and readily bendable if you push on the ends, towards each other. They are all the same diameter, and I am going to bundle them together in parallel one to another, a whole lot of them. Two of them will come into contact. I've made cross section thru them, they come into contact like that, and now they can't get any closer to each other. They are actually tangent. A third one will nest in top of the two it makes it a triangle. I find that I can get six around one making the hexagon and so on. We went into that pattern yesterday. I can get another row around, and another row, and they get into a hexagonal pattern of closest packing. And I take a large number of these rods, and I've counted them out so they are going to come out in even hexagons not just partial rings of the outer set. And, I bring them together, and finally you keep doing this to them and you finally get into that closest packing very much tighter than they were at first. Now we put a tensile strap around them to hold them in their closest packing, so we wrap them all the way around, the whole length of this. Get it absolutely tight they bound together. Now, I made so many of them that we have a total bundle about six inches in diameter, and it is four feet long, so its length to diameter ratio is twelve to one. You find there is something in columns, compression columns that we call slenderness ratio.