Reduction, mechanism and all that

Why I am a heretic

The name of this blog recognizes that some of my views are seen by many to be obviously wrong.  An example of this cropped up recently, when I posted a comment on John Wilkins’ blog.  John seemed to think that I was obviously wrong, though another commenter seemed to agree with me.

Evidently the way I look at the issues is very different from the way that John (and many others) look at the same issues.  This post is intended to discuss those differences in viewpoint, as best I understand them.

Mathematical duality (2)

In an earlier post  I discussed the idea of mathematical duality, and I used the duality between the time domain and the frequency domain, as seen with Fourier transforms, to illustrate the idea.

Today, I will discuss the simpler duality that we see in linear algebra (the study of vector spaces).  This will only be an overview.  There are many fine textbooks on linear algebra if you are looking for a more detailed discussion.

Sullivan on Obama and Quaddafi

To rid the world of Osama bin Laden, Anwar al-Awlaki and Moammar Qaddafi within six months: if Obama were a Republican, he’d be on Mount Rushmore by now.

From Andrew Sullivan: A Tale Of Two Presidents

The “occupy” movement

A short post in support of the goals of “Occupy Wall Street” and other occupy movements.

One of our two political parties seems to be a wholly owned subsidiary of big business, while the other pays too much deference to corporate interests.  It is good to see an awakening concern that the interests of the people are too often being ignored.

Mathematical duality

There are many dualities that mathematicians study.  In this post, I shall discuss two of them, in order to illustrate some of the ideas involved.

Line, point duality

As a simple example of mathematical duality, consider the duality of points and lines in Euclidean geometry.  And recall from your school days, that when we talk of a line in Euclidean geometry, we are talking of an infinite straight line extended in both directions.  The short “lines” that we actually draw can be called “line segments” so as to distinguish them from the extended lines.

Self-foolery

Said by Jerry Coyne:

Theology is merely an intellectual game of self-foolery. And many theologians are very good at it.

Very well said.  And Jerry’s choice of wording is impeccable.

That pretty much summarizes why I gave up on religion many years ago.  I guess I’m not very good at self-foolery.

Blog changes

Time/date: I have switched to showing UTC (or Greenwich Mean Time) for posting times.  I am making this change in the hope that it will be less confusing.  When reading other blogs, I am never sure what timezone is in use, so I thought it best to use the international standard (UTC).

Another blog:  I have started a second blog, Thoughts on computing.  I have previously made some computing posts here, although that is strictly outside the intended subject matter for this blog.  Future computing related posts will be at the new blog, and might be more frequent than past computing posts.

Certificates for dummies

This post is an attempt to provide a simple introduction to security certificates, as used on the web – also known as PKI (public key infrastructure) and X.509 (a series of standards).

Acknowledgement: The title of this post is shamelessly stolen from a suggestion in a thread at the opensuse forums.

Security certificates are part of what we use when sending encrypted data to a server (web server, mail server, etc).